This document discusses optimizing the client-side performance of websites. It describes how reducing HTTP requests through techniques like image maps, CSS sprites, and combining scripts and stylesheets can improve response times. It also recommends strategies like using a content delivery network, adding expiration headers, compressing components, correctly structuring CSS and scripts, and optimizing JavaScript code and Ajax implementations. The benefits of a performant front-end are emphasized, as client-side optimizations often require less time and resources than back-end changes.
The Semantic Web is a vision of information that is understandable by computers. Although there is great exploitable potential, we are still in "Generation Zero'' of the Semantic Web, since there are few real-world compelling applications. The heterogeneity, the volume of data and the lack of standards are problems that could be addressed through some nature inspired methods. The paper presents the most important aspects of the Semantic Web, as well as its biggest issues; it then describes some methods inspired from nature - genetic algorithms, artificial neural networks, swarm intelligence, and the way these techniques can be used to deal with Semantic Web problems.
The Web is a universal medium for information, data and knowledge exchange. The Semantic Web is an extension of the World Wide Web, ``in which information is given well-defined meaning, better enabling computers and people to work in cooperation''\cite{semweb:lee}. RDF, together with SparQL, provide a powerful mechanism for describing and interchanging metadata on the web. This paper presents briefly the two concepts - RDF, SparQL - and three of the most popular frameworks (written in Java) that offer support for RDF: Jena, Sesame and JRDF.
Improve information retrieval and e learning usingIJwest
The Web-based education and E-Learning has become a very important branch of new educational technology. E-learning and Web-based courses offer advantages for learners by making access to resources and learning objects very fast, just-in-time and relevance, at any time or place. Web based Learning Management Systems should focus on how to satisfy the e-learners needs and it may advise a learner with most suitable resources and learning objects. But Because of many limitations using web 2.0 for creating E-learning management system, now-a-days we use Web 3.0 which is known as Semantic web. It is a platform to represent E-learning management system that recovers the limitations of Web 2.0.In this paper we present “improve information retrieval and e-learning using mobile agent based on semantic web technology”. This paper focuses on design and implementation of knowledge-based industrial reusable, interactive, web-based training activities at the sea ports and logistics sector and use e-learning system and semantic web to deliver the learning objects to learners in an interactive, adaptive and flexible manner. We use semantic web and mobile agent to improve Library and courses Search. The architecture presented in this paper is considered an adaptation model that converts from syntactic search to semantic search. We apply the training at Damietta port in Egypt as a real-world case study. we present one of possible applications of mobile agent technology based on semantic web to management of Web Services, this model improve the information retrieval and E-learning system.
Information residing in relational databases and delimited file systems are inadequate for reuse and sharing over the web. These file systems do not adhere to commonly set principles for maintaining data harmony. Due to these reasons, the resources have been suffering from lack of uniformity, heterogeneity as well as redundancy throughout the web. Ontologies have been widely used for solving such type of problems, as they help in extracting knowledge out of any information system. In this article, we focus on extracting concepts and their relations from a set of CSV files. These files are served as individual concepts and grouped into a particular domain, called the domain ontology. Furthermore, this domain ontology is used for capturing CSV data and represented in RDF format retaining links among files or concepts. Datatype and object properties are automatically detected from header fields. This reduces the task of user involvement in generating mapping files. The detail analysis has been performed on Baseball tabular data and the result shows a rich set of semantic information.
Ontology languages are used in modelling the semantics of concepts within a particular domain and the relationships between those concepts. The Semantic Web standard provides a number of modelling languages that differ in their level of expressivity and are organized in a Semantic Web Stack in such a way that each language level builds on the expressivity of the other. There are several problems when one attempts to use independently developed ontologies. When existing ontologies are adapted for new purposes it requires that certain operations are performed on them. These operations are currently performed in a semi-automated manner. This paper seeks to model categorically the syntax and semantics of RDF ontology as a step towards the formalization of ontological operations using category theory.
Semantic Annotation: The Mainstay of Semantic WebEditor IJCATR
Given that semantic Web realization is based on the critical mass of metadata accessibility and the representation of data with formal
knowledge, it needs to generate metadata that is specific, easy to understand and well-defined. However, semantic annotation of the
web documents is the successful way to make the Semantic Web vision a reality. This paper introduces the Semantic Web and its
vision (stack layers) with regard to some concept definitions that helps the understanding of semantic annotation. Additionally, this
paper introduces the semantic annotation categories, tools, domains and models
While the world is witnessing an information revolution unprecedented and great speed in the growth of databases in all aspects. Databases interconnect with their content and schema but use different elements and structures to express the same concepts and relations, which may cause semantic and structural conflicts. This paper proposes a new technique for integration the heterogeneous eXtensible Markup Language (XML) schemas, under the name XDEHD. The returned mediated schema contains all concepts and relations of the sources without duplication. Detailed technique divides into three steps; First, extract all subschemas from the sources by decompose the schemas sources, each subschema contains three levels, these levels are ancestor, root and leaf. Thereafter, second, the technique matches and compares the subschemas and return the related candidate subschemas, semantic closeness function is implemented to measures the degree how similar the concepts of subschemas are modelled in the sources. Finally, create the medicate schema by integration the candidate subschemas, and then obtain the minimal and complete unified schema, association strength function is developed to compute closely of pair in candidate subschema across all data sources, and elements repetition function is employed to calculate how many times each element repeated between the candidate subschema.
The logic-based machine-understandable framework of the Semantic Web often challenges naive users when they try to query ontology-based knowledge bases. Existing research efforts have approached this problem by introducing Natural Language (NL) interfaces to ontologies. These NL interfaces have the ability to construct SPARQL queries based on NL user queries. However, most efforts were restricted to queries expressed in English, and they often benefited from the advancement of English NLP tools. However, little research has been done to support querying the Arabic content on the Semantic Web by using NL queries. This paper presents a domain-independent approach to translate Arabic NL queries to SPARQL by leveraging linguistic analysis. Based on a special consideration on Noun Phrases (NPs), our approach uses a language parser to extract NPs and the relations from Arabic parse trees and match them to the underlying ontology. It then utilizes knowledge in the ontology to group NPs into triple-based representations. A SPARQL query is finally generated by extracting targets and modifiers, and interpreting them into SPARQL. The interpretation of advanced semantic features including negation, conjunctive and disjunctive modifiers is also supported. The approach was evaluated by using two datasets consisting of OWL test data and queries, and the obtained results have confirmed its feasibility to translate Arabic NL queries to SPARQL.
The Semantic Web is a vision of information that is understandable by computers. Although there is great exploitable potential, we are still in "Generation Zero'' of the Semantic Web, since there are few real-world compelling applications. The heterogeneity, the volume of data and the lack of standards are problems that could be addressed through some nature inspired methods. The paper presents the most important aspects of the Semantic Web, as well as its biggest issues; it then describes some methods inspired from nature - genetic algorithms, artificial neural networks, swarm intelligence, and the way these techniques can be used to deal with Semantic Web problems.
The Web is a universal medium for information, data and knowledge exchange. The Semantic Web is an extension of the World Wide Web, ``in which information is given well-defined meaning, better enabling computers and people to work in cooperation''\cite{semweb:lee}. RDF, together with SparQL, provide a powerful mechanism for describing and interchanging metadata on the web. This paper presents briefly the two concepts - RDF, SparQL - and three of the most popular frameworks (written in Java) that offer support for RDF: Jena, Sesame and JRDF.
Improve information retrieval and e learning usingIJwest
The Web-based education and E-Learning has become a very important branch of new educational technology. E-learning and Web-based courses offer advantages for learners by making access to resources and learning objects very fast, just-in-time and relevance, at any time or place. Web based Learning Management Systems should focus on how to satisfy the e-learners needs and it may advise a learner with most suitable resources and learning objects. But Because of many limitations using web 2.0 for creating E-learning management system, now-a-days we use Web 3.0 which is known as Semantic web. It is a platform to represent E-learning management system that recovers the limitations of Web 2.0.In this paper we present “improve information retrieval and e-learning using mobile agent based on semantic web technology”. This paper focuses on design and implementation of knowledge-based industrial reusable, interactive, web-based training activities at the sea ports and logistics sector and use e-learning system and semantic web to deliver the learning objects to learners in an interactive, adaptive and flexible manner. We use semantic web and mobile agent to improve Library and courses Search. The architecture presented in this paper is considered an adaptation model that converts from syntactic search to semantic search. We apply the training at Damietta port in Egypt as a real-world case study. we present one of possible applications of mobile agent technology based on semantic web to management of Web Services, this model improve the information retrieval and E-learning system.
Information residing in relational databases and delimited file systems are inadequate for reuse and sharing over the web. These file systems do not adhere to commonly set principles for maintaining data harmony. Due to these reasons, the resources have been suffering from lack of uniformity, heterogeneity as well as redundancy throughout the web. Ontologies have been widely used for solving such type of problems, as they help in extracting knowledge out of any information system. In this article, we focus on extracting concepts and their relations from a set of CSV files. These files are served as individual concepts and grouped into a particular domain, called the domain ontology. Furthermore, this domain ontology is used for capturing CSV data and represented in RDF format retaining links among files or concepts. Datatype and object properties are automatically detected from header fields. This reduces the task of user involvement in generating mapping files. The detail analysis has been performed on Baseball tabular data and the result shows a rich set of semantic information.
Ontology languages are used in modelling the semantics of concepts within a particular domain and the relationships between those concepts. The Semantic Web standard provides a number of modelling languages that differ in their level of expressivity and are organized in a Semantic Web Stack in such a way that each language level builds on the expressivity of the other. There are several problems when one attempts to use independently developed ontologies. When existing ontologies are adapted for new purposes it requires that certain operations are performed on them. These operations are currently performed in a semi-automated manner. This paper seeks to model categorically the syntax and semantics of RDF ontology as a step towards the formalization of ontological operations using category theory.
Semantic Annotation: The Mainstay of Semantic WebEditor IJCATR
Given that semantic Web realization is based on the critical mass of metadata accessibility and the representation of data with formal
knowledge, it needs to generate metadata that is specific, easy to understand and well-defined. However, semantic annotation of the
web documents is the successful way to make the Semantic Web vision a reality. This paper introduces the Semantic Web and its
vision (stack layers) with regard to some concept definitions that helps the understanding of semantic annotation. Additionally, this
paper introduces the semantic annotation categories, tools, domains and models
While the world is witnessing an information revolution unprecedented and great speed in the growth of databases in all aspects. Databases interconnect with their content and schema but use different elements and structures to express the same concepts and relations, which may cause semantic and structural conflicts. This paper proposes a new technique for integration the heterogeneous eXtensible Markup Language (XML) schemas, under the name XDEHD. The returned mediated schema contains all concepts and relations of the sources without duplication. Detailed technique divides into three steps; First, extract all subschemas from the sources by decompose the schemas sources, each subschema contains three levels, these levels are ancestor, root and leaf. Thereafter, second, the technique matches and compares the subschemas and return the related candidate subschemas, semantic closeness function is implemented to measures the degree how similar the concepts of subschemas are modelled in the sources. Finally, create the medicate schema by integration the candidate subschemas, and then obtain the minimal and complete unified schema, association strength function is developed to compute closely of pair in candidate subschema across all data sources, and elements repetition function is employed to calculate how many times each element repeated between the candidate subschema.
The logic-based machine-understandable framework of the Semantic Web often challenges naive users when they try to query ontology-based knowledge bases. Existing research efforts have approached this problem by introducing Natural Language (NL) interfaces to ontologies. These NL interfaces have the ability to construct SPARQL queries based on NL user queries. However, most efforts were restricted to queries expressed in English, and they often benefited from the advancement of English NLP tools. However, little research has been done to support querying the Arabic content on the Semantic Web by using NL queries. This paper presents a domain-independent approach to translate Arabic NL queries to SPARQL by leveraging linguistic analysis. Based on a special consideration on Noun Phrases (NPs), our approach uses a language parser to extract NPs and the relations from Arabic parse trees and match them to the underlying ontology. It then utilizes knowledge in the ontology to group NPs into triple-based representations. A SPARQL query is finally generated by extracting targets and modifiers, and interpreting them into SPARQL. The interpretation of advanced semantic features including negation, conjunctive and disjunctive modifiers is also supported. The approach was evaluated by using two datasets consisting of OWL test data and queries, and the obtained results have confirmed its feasibility to translate Arabic NL queries to SPARQL.
Although of the semantic web technologies utilization in the learning development field is a new research area, some authors have already proposed their idea of how an effective that operate. Specifically, from analysis of the literature in the field, we have identified three different types of existing applications that actually employ these technologies to support learning. These applications aim at: Enhancing the learning objects reusability by linking them to an ontological description of the domain, or, more generally, describe relevant dimension of the learning process in an ontology, then; providing a comprehensive authoring system to retrieve and organize web material into a learning course, and constructing advanced strategies to present annotated resources to the user, in the form of browsing facilities, narrative generation and final rendering of a course. On difference with the approaches cited above, here we propose an approach that is modeled on narrative studies and on their transposition in the digital world. In the rest of the paper, we present the theoretical basis that inspires this approach, and show some examples that are guiding our implementation and testing of these ideas within e-learning. By emerging the idea of the ontologies are recognized as the most important component in achieving semantic interoperability of e-learning resources. The benefits of their use have already been recognized in the learning technology community. In order to better define different aspects of ontology applications in e-learning, researchers have given several classifications of ontologies. We refer to a general one given in that differentiates between three dimensions ontologies can describe: content, context, and structure. Most of the present research has been dedicated to the first group of ontologies. A well-known example of such an ontology is based on the ACM Computer Classification System (ACM CCS) and defined by Resource Description Framework Schema (RDFS). It’s used in the MOODLE to classify learning objects with a goal to improve searching. The chapter will cover the terms of the semantic web and e-learning systems design and management in e-learning (MOODLE) and some of studies depend on e-learning and semantic web, thus the tools will be used in this paper, and lastly we shall discuss the expected contribution. The special attention will be putted on the above topics.
Nelson Piedra , Janneth Chicaiza
and Jorge López, Universidad Técnica Particular de Loja, Edmundo
Tovar, Universidad Politécnica de Madrid,
and Oscar Martínez, Universitas
Miguel Hernández
Explore the advantages of using linked data with OERs.
Concept hierarchy is the backbone of ontology, and the concept hierarchy acquisition has been a hot topic in the field of ontology learning. this paper proposes a hyponymy extraction method of domain ontology concept based on cascaded conditional random field(CCRFs) and hierarchy clustering. It takes free text as extracting object, adopts CCRFs identifying the domain concepts. First the low layer of CCRFs is used to identify simple domain concept, then the results are sent to the high layer, in which the nesting concepts are recognized. Next we adopt hierarchy clustering to identify the hyponymy relation between domain ontology concepts. The experimental results demonstrate the proposed method is efficient.
Semantics in Financial Services -David NewmanPeter Berger
David Newman serves as a Senior Architect in the Enterprise Architecture group at Wells Fargo Bank. He has been following semantic technology for the last 3 years; and has developed several business ontologies. He has been instrumental in thought leadership at Wells Fargo on the application of Semantic Technology and is a representative of the Financial Services Technology Consortium (FSTC)on the W3C SPARQL Working Group.
Semantic Web: Technolgies and Applications for Real-WorldAmit Sheth
Amit Sheth and Susie Stephens, "Semantic Web: Technolgies and Applications for Real-World," Tutorial at 2007 World Wide Web Conference, Banff, Canada.
Tutorial discusses technologies and deployed real-world applications through 2007.
Tutorial description at: http://www2007.org/tutorial-T11.php
Build Narratives, Connect Artifacts: Linked Open Data for Cultural HeritageOntotext
Many issues are faced by scholars, book researchers, museum directors who try to find the underlying connection between resources. Scholars in particular continuously emphasizes the role of digital humanities and the value of linked data in cultural heritage information systems.
Web of Data as a Solution for Interoperability. Case StudiesSabin Buraga
The paper draws several considerations regarding the use of Web of Data (Semantic Web) technologies – such as metadata vocabularies and ontological constructs – to increase the degree of interoperability within distributed systems. A number of case studies are presenting to express the knowledge in a
platform- and programming language-independent manner.
for kids! celebrates 20 years of support for public educaiton in San Mateo and Foster City. Founded by local community leaders, district employees and parents, this local education foundation has donated more than $2.8 million to help fund programs for K-8 public schools in the San Mateo-Foster City School District. With a history of giving to programs such as school libraries, music programs and counseling services, view our focus for the 2009-2010 school year\'s donation and our plans for the future.
Although of the semantic web technologies utilization in the learning development field is a new research area, some authors have already proposed their idea of how an effective that operate. Specifically, from analysis of the literature in the field, we have identified three different types of existing applications that actually employ these technologies to support learning. These applications aim at: Enhancing the learning objects reusability by linking them to an ontological description of the domain, or, more generally, describe relevant dimension of the learning process in an ontology, then; providing a comprehensive authoring system to retrieve and organize web material into a learning course, and constructing advanced strategies to present annotated resources to the user, in the form of browsing facilities, narrative generation and final rendering of a course. On difference with the approaches cited above, here we propose an approach that is modeled on narrative studies and on their transposition in the digital world. In the rest of the paper, we present the theoretical basis that inspires this approach, and show some examples that are guiding our implementation and testing of these ideas within e-learning. By emerging the idea of the ontologies are recognized as the most important component in achieving semantic interoperability of e-learning resources. The benefits of their use have already been recognized in the learning technology community. In order to better define different aspects of ontology applications in e-learning, researchers have given several classifications of ontologies. We refer to a general one given in that differentiates between three dimensions ontologies can describe: content, context, and structure. Most of the present research has been dedicated to the first group of ontologies. A well-known example of such an ontology is based on the ACM Computer Classification System (ACM CCS) and defined by Resource Description Framework Schema (RDFS). It’s used in the MOODLE to classify learning objects with a goal to improve searching. The chapter will cover the terms of the semantic web and e-learning systems design and management in e-learning (MOODLE) and some of studies depend on e-learning and semantic web, thus the tools will be used in this paper, and lastly we shall discuss the expected contribution. The special attention will be putted on the above topics.
Nelson Piedra , Janneth Chicaiza
and Jorge López, Universidad Técnica Particular de Loja, Edmundo
Tovar, Universidad Politécnica de Madrid,
and Oscar Martínez, Universitas
Miguel Hernández
Explore the advantages of using linked data with OERs.
Concept hierarchy is the backbone of ontology, and the concept hierarchy acquisition has been a hot topic in the field of ontology learning. this paper proposes a hyponymy extraction method of domain ontology concept based on cascaded conditional random field(CCRFs) and hierarchy clustering. It takes free text as extracting object, adopts CCRFs identifying the domain concepts. First the low layer of CCRFs is used to identify simple domain concept, then the results are sent to the high layer, in which the nesting concepts are recognized. Next we adopt hierarchy clustering to identify the hyponymy relation between domain ontology concepts. The experimental results demonstrate the proposed method is efficient.
Semantics in Financial Services -David NewmanPeter Berger
David Newman serves as a Senior Architect in the Enterprise Architecture group at Wells Fargo Bank. He has been following semantic technology for the last 3 years; and has developed several business ontologies. He has been instrumental in thought leadership at Wells Fargo on the application of Semantic Technology and is a representative of the Financial Services Technology Consortium (FSTC)on the W3C SPARQL Working Group.
Semantic Web: Technolgies and Applications for Real-WorldAmit Sheth
Amit Sheth and Susie Stephens, "Semantic Web: Technolgies and Applications for Real-World," Tutorial at 2007 World Wide Web Conference, Banff, Canada.
Tutorial discusses technologies and deployed real-world applications through 2007.
Tutorial description at: http://www2007.org/tutorial-T11.php
Build Narratives, Connect Artifacts: Linked Open Data for Cultural HeritageOntotext
Many issues are faced by scholars, book researchers, museum directors who try to find the underlying connection between resources. Scholars in particular continuously emphasizes the role of digital humanities and the value of linked data in cultural heritage information systems.
Web of Data as a Solution for Interoperability. Case StudiesSabin Buraga
The paper draws several considerations regarding the use of Web of Data (Semantic Web) technologies – such as metadata vocabularies and ontological constructs – to increase the degree of interoperability within distributed systems. A number of case studies are presenting to express the knowledge in a
platform- and programming language-independent manner.
for kids! celebrates 20 years of support for public educaiton in San Mateo and Foster City. Founded by local community leaders, district employees and parents, this local education foundation has donated more than $2.8 million to help fund programs for K-8 public schools in the San Mateo-Foster City School District. With a history of giving to programs such as school libraries, music programs and counseling services, view our focus for the 2009-2010 school year\'s donation and our plans for the future.
Principalul obiectiv al îmbunătățirii este să proceseze o imagine, astfel încât rezultatul să devină mai potrivit decât originalul pentru o anumită aplicaţie. Cuvântul specific este foarte important, pentru că stabileşte de la bun început faptul că tehnicile discutate sunt într-o mare măsură orientate spre problemă. În acest fel, de exemplu, este posibil ca o metodă care este utilă pentru îmbunătăţirea imaginilor realizate cu ajutorul razelor X să nu fie cea mai bună abordare pentru îmbunătăţirea imaginilor de pe Marte transmise de sondele spaţiale.
WebSpa is a tool that allows the quick, intuitive (and even fun) interrogation of arbitrary SPARQL endpoints. WebSpa runs in the web browser and does not require the installation of any additional software. The tool manages a large variety of pre-defined SPARQL endpoints and allows the addition of new ones. An user account gives the possibility of saving both the interrogation and its results on the local computer, as well as further editing of the queries. The application is written in both Java and Flex. It uses Jena and ARQ application programming interface in order to perform the queries, and the results are processed and displayed using Flex.
When initial work on an XML-based graphics interchange format began, the natural first thought was to use SVG. However, there are key differences between SVG and Flash Player's graphics capabilities. These include core differences in SVG and Flash's rendering model with regards to filters, transforms and text. Additionally, the interchange format needed to be able to support future Flash Player features, which would not necessarily map to SVG features. As such, the decision was made to go with a new interchange format, FXG, instead of having a non-standard implementation of SVG. FXG does borrow from SVG whenever possible.
Evolution Towards Web 3.0: The Semantic WebLeeFeigenbaum
This was a lecture I presented at Professor Stuart Madnick's class, "Evolution Towards Web 3.0" at the MIT Sloan School of Management on April 21, 2011. Please follow along with the speaker notes which add significant commentary to the slides.
Client Side Performance In Web Applicationsvladungureanu
Client-side optimization for web applications is an important issue that must be considered by any web developer. This paper presents some approaches regarding web applications client-side optimization. We
discuss the optimization techniques that refer to CSS, JavaScript and HTML. We also we oer a preview on various tools that can be used for proling, debugging and optimizing, such as Firebug. The final part of the paper sums some conclusions regarding client-side optimization.
Are you trying to improve your website performance? Read the blog to find some handpicked strategies. Implement these and note the difference! https://www.webguru-india.com/blog/tips-to-improve-your-website-performance/
Did you know that 80% to 90% of the user's page-load time comes from components outside the firewall? Optimizing performance on the front end (e.g. from the client side) can enhance the user experience by reducing the response times of your web pages and making them load and render much faster.
Optimizing Performance in MEAN Stack Apps.pptxMicrosoft azure
In the current fast-evolving web development environment, the importance of developing applications that provide a smooth user experience cannot be emphasized. A significant factor in attaining this objective stays within the sphere of performance improvement of MEAN Stack applications. Apart from just enhancing the user experience, the advantages expand to strengthening search engine standings and upgrading conversion rates. Therefore, by systematically fine-tuning database design, combining caching mechanisms, and reducing HTTP requests, developers holding the knowledge of MEAN Stack Training in Noida may ensure rapid load times and effortless interactions.
Optimizing Performance in MEAN Stack Apps.pptxMicrosoft azure
Apart from just enhancing the user experience, the advantages expand to strengthening search engine standings and upgrading conversion rates. Therefore, by systematically fine-tuning database design, combining caching mechanisms, and reducing HTTP requests, developers holding the knowledge of MEAN Stack Training in Noida may ensure rapid load times and effortless interactions.
7 secrets of performance oriented front end development servicesKaty Slemon
Why a good front-end is the primary necessity of any digital solution and how can you, as a web/mobile designer or app owner, can be built a performance-optimized front-end for its users.
Best practices to increase the performance of web-based applicationsMouhamad Kawas
In today’s world, technology development aspects are growing rapidly in a way that makes the development of these aspects unacceptable to slowdown.
Perhaps the most distinguishing aspect is the World Wide Web which is considered as the main container for these prospects, despite of the challenges and the difficulties which have faced it since the beginning especially in term of performance.
This paper states current performance difficulties that face web-based applications, grouping these difficulties into categories based on the web technology used. It also proposes a number of recommendations and enhancements that increase and optimize the web performance> These recommendations are implemented in a real case which is “Mofadalah” web-based application at the Syrian ministry of health.
As we all know that speed is one of the most important issues for the success of a website. No one wants to wait for a site to load and that’s why we need to minimize the loading period when building a Joomla website.
The presentation of the Drupal frontend optimizations from Drupal Camp LA 2011. The slides go over optimizations you do in the backend to serve files in the frontend faster and optimizations in the front end to css and javascript to make that aspect run faster.
I felt necessity of creating this brief slideshow, so as to help PHP Developer interns and communicating the intricacies of development with my clients easier. I thought the more deeply clients understood what really went into translating their ideas to web applications under the hood, the better it could translate to
exchange of design issues,
appreciation of development process intricacies, resulting delivery time & cost issues.
So I quickly put together information that I found on internet & have tried to make an attempt. Hope this helps other developers too... Your comments & critique are welcome in terms of improving & simplifying this slide show.
Monitoring web application response times, a new approachMark Friedman
An approach to capturing and integrating web client Real User Measurements from the Navigation object with server-side network and HttpServer diagnostic events.
IWMW 2003: C7 Bandwidth Management Techniques: Technical And Policy IssuesIWMW
Slides used in workshop session C7 on "Bandwidth Management Techniques: Technical And Policy Issues" at the IWMW 2003 event held at the University of Kent on 11-13 June 2003.
See http://www.ukoln.ac.uk/web-focus/events/workshops/webmaster-2003/sessions/#workshops-c
load speed problems of web resources on the client side classification and ...INFOGAIN PUBLICATION
This article is concerned about client side issues of web resources load process related to user agents (browsers) behavior. a lot of modern problems such as improving global availability and reducing bandwidth, the main problem they address is latency: the amount of time it takes for the host server to receive, process, and deliver on a request for a page resource (images, css files, etc.). latency depends largely on how far away the user is from the server, and it’s compounded by the number of resources a web page contains; current load algorithms are investigated and all known solutions with their area or efficiency are explained. We have described four main optimization methods.
Liquidizer.js: A Responsive Web Design Algorithmtheijes
Internet technology is dynamically changing at lightning speeds that the academic brains cannot absorb.
Emerging technologies such as Internet of Things (IoT), fog computing, cloud computing and just to mention a
few have recently emerged as novel technologies. These technologies have not yet sunk in to the minds of
academic scholars, while superior techniques are currently emerging. As a result of these fluid changes, the
study is intrigued by the Responsive Web Design (RWD) technology. RWD is a novel paradigm to develop one
single website for different screen sizes of smart phones, tablets, laptops, and desktops among others. The
websites become responsive by being accessible anytime, anywhere, and on any such devices. Although lots of
ink has been spilled on responsive algorithm framework development, the study developed an enhanced
algorithm with dynamic attributes such as text color, background color, font family, and font size manipulation.
These attributes can be changed on the fly and be accessed by a single line of code by web designers. The
methodology employed to develop the algorithm was jQuery library framework. The outcome of the study was
threefold; first, to develop an enhanced algorithm coined Liquidizer.js, second, to distribute the source code of
Liquidizer.js under the GNU General Public License, and third, to extend the jQuery library platform.
Similar to Website Performance at Client Level (20)
Accelerate your Kubernetes clusters with Varnish CachingThijs Feryn
A presentation about the usage and availability of Varnish on Kubernetes. This talk explores the capabilities of Varnish caching and shows how to use the Varnish Helm chart to deploy it to Kubernetes.
This presentation was delivered at K8SUG Singapore. See https://feryn.eu/presentations/accelerate-your-kubernetes-clusters-with-varnish-caching-k8sug-singapore-28-2024 for more details.
The Art of the Pitch: WordPress Relationships and SalesLaura Byrne
Clients don’t know what they don’t know. What web solutions are right for them? How does WordPress come into the picture? How do you make sure you understand scope and timeline? What do you do if sometime changes?
All these questions and more will be explored as we talk about matching clients’ needs with what your agency offers without pulling teeth or pulling your hair out. Practical tips, and strategies for successful relationship building that leads to closing the deal.
SAP Sapphire 2024 - ASUG301 building better apps with SAP Fiori.pdfPeter Spielvogel
Building better applications for business users with SAP Fiori.
• What is SAP Fiori and why it matters to you
• How a better user experience drives measurable business benefits
• How to get started with SAP Fiori today
• How SAP Fiori elements accelerates application development
• How SAP Build Code includes SAP Fiori tools and other generative artificial intelligence capabilities
• How SAP Fiori paves the way for using AI in SAP apps
GDG Cloud Southlake #33: Boule & Rebala: Effective AppSec in SDLC using Deplo...James Anderson
Effective Application Security in Software Delivery lifecycle using Deployment Firewall and DBOM
The modern software delivery process (or the CI/CD process) includes many tools, distributed teams, open-source code, and cloud platforms. Constant focus on speed to release software to market, along with the traditional slow and manual security checks has caused gaps in continuous security as an important piece in the software supply chain. Today organizations feel more susceptible to external and internal cyber threats due to the vast attack surface in their applications supply chain and the lack of end-to-end governance and risk management.
The software team must secure its software delivery process to avoid vulnerability and security breaches. This needs to be achieved with existing tool chains and without extensive rework of the delivery processes. This talk will present strategies and techniques for providing visibility into the true risk of the existing vulnerabilities, preventing the introduction of security issues in the software, resolving vulnerabilities in production environments quickly, and capturing the deployment bill of materials (DBOM).
Speakers:
Bob Boule
Robert Boule is a technology enthusiast with PASSION for technology and making things work along with a knack for helping others understand how things work. He comes with around 20 years of solution engineering experience in application security, software continuous delivery, and SaaS platforms. He is known for his dynamic presentations in CI/CD and application security integrated in software delivery lifecycle.
Gopinath Rebala
Gopinath Rebala is the CTO of OpsMx, where he has overall responsibility for the machine learning and data processing architectures for Secure Software Delivery. Gopi also has a strong connection with our customers, leading design and architecture for strategic implementations. Gopi is a frequent speaker and well-known leader in continuous delivery and integrating security into software delivery.
Dev Dives: Train smarter, not harder – active learning and UiPath LLMs for do...UiPathCommunity
💥 Speed, accuracy, and scaling – discover the superpowers of GenAI in action with UiPath Document Understanding and Communications Mining™:
See how to accelerate model training and optimize model performance with active learning
Learn about the latest enhancements to out-of-the-box document processing – with little to no training required
Get an exclusive demo of the new family of UiPath LLMs – GenAI models specialized for processing different types of documents and messages
This is a hands-on session specifically designed for automation developers and AI enthusiasts seeking to enhance their knowledge in leveraging the latest intelligent document processing capabilities offered by UiPath.
Speakers:
👨🏫 Andras Palfi, Senior Product Manager, UiPath
👩🏫 Lenka Dulovicova, Product Program Manager, UiPath
Why You Should Replace Windows 11 with Nitrux Linux 3.5.0 for enhanced perfor...SOFTTECHHUB
The choice of an operating system plays a pivotal role in shaping our computing experience. For decades, Microsoft's Windows has dominated the market, offering a familiar and widely adopted platform for personal and professional use. However, as technological advancements continue to push the boundaries of innovation, alternative operating systems have emerged, challenging the status quo and offering users a fresh perspective on computing.
One such alternative that has garnered significant attention and acclaim is Nitrux Linux 3.5.0, a sleek, powerful, and user-friendly Linux distribution that promises to redefine the way we interact with our devices. With its focus on performance, security, and customization, Nitrux Linux presents a compelling case for those seeking to break free from the constraints of proprietary software and embrace the freedom and flexibility of open-source computing.
PHP Frameworks: I want to break free (IPC Berlin 2024)Ralf Eggert
In this presentation, we examine the challenges and limitations of relying too heavily on PHP frameworks in web development. We discuss the history of PHP and its frameworks to understand how this dependence has evolved. The focus will be on providing concrete tips and strategies to reduce reliance on these frameworks, based on real-world examples and practical considerations. The goal is to equip developers with the skills and knowledge to create more flexible and future-proof web applications. We'll explore the importance of maintaining autonomy in a rapidly changing tech landscape and how to make informed decisions in PHP development.
This talk is aimed at encouraging a more independent approach to using PHP frameworks, moving towards a more flexible and future-proof approach to PHP development.
Removing Uninteresting Bytes in Software FuzzingAftab Hussain
Imagine a world where software fuzzing, the process of mutating bytes in test seeds to uncover hidden and erroneous program behaviors, becomes faster and more effective. A lot depends on the initial seeds, which can significantly dictate the trajectory of a fuzzing campaign, particularly in terms of how long it takes to uncover interesting behaviour in your code. We introduce DIAR, a technique designed to speedup fuzzing campaigns by pinpointing and eliminating those uninteresting bytes in the seeds. Picture this: instead of wasting valuable resources on meaningless mutations in large, bloated seeds, DIAR removes the unnecessary bytes, streamlining the entire process.
In this work, we equipped AFL, a popular fuzzer, with DIAR and examined two critical Linux libraries -- Libxml's xmllint, a tool for parsing xml documents, and Binutil's readelf, an essential debugging and security analysis command-line tool used to display detailed information about ELF (Executable and Linkable Format). Our preliminary results show that AFL+DIAR does not only discover new paths more quickly but also achieves higher coverage overall. This work thus showcases how starting with lean and optimized seeds can lead to faster, more comprehensive fuzzing campaigns -- and DIAR helps you find such seeds.
- These are slides of the talk given at IEEE International Conference on Software Testing Verification and Validation Workshop, ICSTW 2022.
Generative AI Deep Dive: Advancing from Proof of Concept to ProductionAggregage
Join Maher Hanafi, VP of Engineering at Betterworks, in this new session where he'll share a practical framework to transform Gen AI prototypes into impactful products! He'll delve into the complexities of data collection and management, model selection and optimization, and ensuring security, scalability, and responsible use.
Le nuove frontiere dell'AI nell'RPA con UiPath Autopilot™UiPathCommunity
In questo evento online gratuito, organizzato dalla Community Italiana di UiPath, potrai esplorare le nuove funzionalità di Autopilot, il tool che integra l'Intelligenza Artificiale nei processi di sviluppo e utilizzo delle Automazioni.
📕 Vedremo insieme alcuni esempi dell'utilizzo di Autopilot in diversi tool della Suite UiPath:
Autopilot per Studio Web
Autopilot per Studio
Autopilot per Apps
Clipboard AI
GenAI applicata alla Document Understanding
👨🏫👨💻 Speakers:
Stefano Negro, UiPath MVPx3, RPA Tech Lead @ BSP Consultant
Flavio Martinelli, UiPath MVP 2023, Technical Account Manager @UiPath
Andrei Tasca, RPA Solutions Team Lead @NTT Data
GraphRAG is All You need? LLM & Knowledge GraphGuy Korland
Guy Korland, CEO and Co-founder of FalkorDB, will review two articles on the integration of language models with knowledge graphs.
1. Unifying Large Language Models and Knowledge Graphs: A Roadmap.
https://arxiv.org/abs/2306.08302
2. Microsoft Research's GraphRAG paper and a review paper on various uses of knowledge graphs:
https://www.microsoft.com/en-us/research/blog/graphrag-unlocking-llm-discovery-on-narrative-private-data/
Alt. GDG Cloud Southlake #33: Boule & Rebala: Effective AppSec in SDLC using ...James Anderson
Effective Application Security in Software Delivery lifecycle using Deployment Firewall and DBOM
The modern software delivery process (or the CI/CD process) includes many tools, distributed teams, open-source code, and cloud platforms. Constant focus on speed to release software to market, along with the traditional slow and manual security checks has caused gaps in continuous security as an important piece in the software supply chain. Today organizations feel more susceptible to external and internal cyber threats due to the vast attack surface in their applications supply chain and the lack of end-to-end governance and risk management.
The software team must secure its software delivery process to avoid vulnerability and security breaches. This needs to be achieved with existing tool chains and without extensive rework of the delivery processes. This talk will present strategies and techniques for providing visibility into the true risk of the existing vulnerabilities, preventing the introduction of security issues in the software, resolving vulnerabilities in production environments quickly, and capturing the deployment bill of materials (DBOM).
Speakers:
Bob Boule
Robert Boule is a technology enthusiast with PASSION for technology and making things work along with a knack for helping others understand how things work. He comes with around 20 years of solution engineering experience in application security, software continuous delivery, and SaaS platforms. He is known for his dynamic presentations in CI/CD and application security integrated in software delivery lifecycle.
Gopinath Rebala
Gopinath Rebala is the CTO of OpsMx, where he has overall responsibility for the machine learning and data processing architectures for Secure Software Delivery. Gopi also has a strong connection with our customers, leading design and architecture for strategic implementations. Gopi is a frequent speaker and well-known leader in continuous delivery and integrating security into software delivery.
LF Energy Webinar: Electrical Grid Modelling and Simulation Through PowSyBl -...DanBrown980551
Do you want to learn how to model and simulate an electrical network from scratch in under an hour?
Then welcome to this PowSyBl workshop, hosted by Rte, the French Transmission System Operator (TSO)!
During the webinar, you will discover the PowSyBl ecosystem as well as handle and study an electrical network through an interactive Python notebook.
PowSyBl is an open source project hosted by LF Energy, which offers a comprehensive set of features for electrical grid modelling and simulation. Among other advanced features, PowSyBl provides:
- A fully editable and extendable library for grid component modelling;
- Visualization tools to display your network;
- Grid simulation tools, such as power flows, security analyses (with or without remedial actions) and sensitivity analyses;
The framework is mostly written in Java, with a Python binding so that Python developers can access PowSyBl functionalities as well.
What you will learn during the webinar:
- For beginners: discover PowSyBl's functionalities through a quick general presentation and the notebook, without needing any expert coding skills;
- For advanced developers: master the skills to efficiently apply PowSyBl functionalities to your real-world scenarios.
A tale of scale & speed: How the US Navy is enabling software delivery from l...sonjaschweigert1
Rapid and secure feature delivery is a goal across every application team and every branch of the DoD. The Navy’s DevSecOps platform, Party Barge, has achieved:
- Reduction in onboarding time from 5 weeks to 1 day
- Improved developer experience and productivity through actionable findings and reduction of false positives
- Maintenance of superior security standards and inherent policy enforcement with Authorization to Operate (ATO)
Development teams can ship efficiently and ensure applications are cyber ready for Navy Authorizing Officials (AOs). In this webinar, Sigma Defense and Anchore will give attendees a look behind the scenes and demo secure pipeline automation and security artifacts that speed up application ATO and time to production.
We will cover:
- How to remove silos in DevSecOps
- How to build efficient development pipeline roles and component templates
- How to deliver security artifacts that matter for ATO’s (SBOMs, vulnerability reports, and policy evidence)
- How to streamline operations with automated policy checks on container images
State of ICS and IoT Cyber Threat Landscape Report 2024 previewPrayukth K V
The IoT and OT threat landscape report has been prepared by the Threat Research Team at Sectrio using data from Sectrio, cyber threat intelligence farming facilities spread across over 85 cities around the world. In addition, Sectrio also runs AI-based advanced threat and payload engagement facilities that serve as sinks to attract and engage sophisticated threat actors, and newer malware including new variants and latent threats that are at an earlier stage of development.
The latest edition of the OT/ICS and IoT security Threat Landscape Report 2024 also covers:
State of global ICS asset and network exposure
Sectoral targets and attacks as well as the cost of ransom
Global APT activity, AI usage, actor and tactic profiles, and implications
Rise in volumes of AI-powered cyberattacks
Major cyber events in 2024
Malware and malicious payload trends
Cyberattack types and targets
Vulnerability exploit attempts on CVEs
Attacks on counties – USA
Expansion of bot farms – how, where, and why
In-depth analysis of the cyber threat landscape across North America, South America, Europe, APAC, and the Middle East
Why are attacks on smart factories rising?
Cyber risk predictions
Axis of attacks – Europe
Systemic attacks in the Middle East
Download the full report from here:
https://sectrio.com/resources/ot-threat-landscape-reports/sectrio-releases-ot-ics-and-iot-security-threat-landscape-report-2024/
State of ICS and IoT Cyber Threat Landscape Report 2024 preview
Website Performance at Client Level
1. Website Performance at Client Level
Monica Macoveiciuc and Constantin Stan
Faculty of Computer Science, Alexandru Ioan Cuza University, Iasi
Abstract. This paper describes the importance of a performant pre-
sentation tier. It presents the easiest way of optimizing the client-side
code, providing source code examples for good practices. It then shows
the correct approach to using CSS and HTML and the impact it has
on the website response time. The Ajax techonolgy is briefly described,
emphasizing the role of JavaScript and presenting methods for improv-
ing its performance. In the end, some popular tools for monitoring and
testing web applications are introduces.
2. Introduction. The Importance of a Performant
Presentation Tier
Multi-tier architecture (often referred to as N-tier architecture) is a client-server
architecture in which the presentation, the application processing, and the data
management are logically separate processes. There are many business benefits
to N-Tier Architecture. For example, a small business can begin running all tiers
on a single machine. As traffic and business increases, each tier can be expanded
and moved to its own machine and then clustered. This is just one example of
how N-Tier Architecture improves scalability and supports cost-efficient appli-
cation building.
The presentation tier is the topmost level of the application. It communicates
with other tiers by outputting results to the browser/client tier and all other
tiers in the network.
Client-side programming is based on the idea that the CPU power of the com-
puter which the client is using to browse the web can be also exploit. Things
like processing simple requests, maintaining state, and the presentation tier are
handled by the web surfer’s own computer instead of being handled by some
web server hosting a site.
Web page optimization streamlines the content to maximize display speed. Fast
display speed is the key to success for a website. It increases profits, decreases
costs, and improves customer. The front-end is the most accessible part of a
website. Many times, the access to the server is limited and, even if one has the
permissions to modify the web server or the database, improving their perfor-
mance requires specialized knowledge.
There is more potential for improvement by focusing on the front-end. Cutting
it in half reduces response times by 40% or more, whereas cutting back-end per-
formance in half results in less than a 10% reduction. Front-end improvements
typically require less time and resources than back-end projects (redesigning
application architecture and code, finding and optimizing critical code paths,
adding or modifying hardware, distributing databases, etc.). Optimizing the pre-
sentation level is also inexpensive compared to the other levels of application.
3. Optimization
The Performance Golden Rule states that only 10 to 20% of the user response
time involves retrieving the requested HTML document, while the rest of it is
spent on dealing with the retrieved content.
Fewer HTTP Requests
A simple way to improve response time is to reduce the number of HTTP re-
quests, by reducing the number of components. There are different techniques
for achieving this: the use of image maps, CSS sprites, inline images, combined
scripts and stylesheets. The increase in speed is noticeable and, depending on
the website, it can exceed 50%.
Image Maps
It is a common practice to use images for displaying navigation bars or buttons.
These images are associated with URLs and, if one uses multiple hyperlinked
images in this way, image maps may be a way to reduce the number of HTTP
requests without changing the page’s look and feel. Adjacent images can be
compound into one composite image. An image map associates multiple URLs
with this image and the destination URL is chosen based on where the user
clicks on the image. Instead of multiple HTTP requests, this technique requires
only one. For example, the following HTML code:
<div>
<h4>Two Images, with Two HTTP Requests</h4>
<p>
<img src="img1.jpg" alt="First Image">
<img src="img2.jpg" alt="Second Image">
</p>
</div>
can be optimized by using a clientside usemap, the following way:
<div>
<h4>One Combined Image, with One HTTP Request</h4>
<map name="user_map">
<area href="#1" alt="1" title="1" shape="rect"
coords="0,0,100,100">
<area href="#2" alt="2" title="2" shape="rect"
coords="100,0,210,100">
</map>
<img src="combined.jpg" width="210" height="100"
4. alt="Combined image"
usemap="#user_map" border="0">
</div>
The only disadvantage of this approach is that it can easily lead to errors. Defin-
ing the area coordinates of the image maps, if done manually, is tedious. Further
more, it is almost impossible to use any shape other than rectangles.
CSS Sprites
Like image maps, CSS sprites allow you to combine images, but they are much
more flexible. The images in an image map must be contiguous, while the CSS
sprites dont have that limitation. Another advantage of using them is the reduced
download size - the combined image tends to be smaller than the sum of the
separate images as a result of reducing the amount of image overhead (color
tables, formatting information, etc.). Moreover,it results in clean markup and
fewer images to deal with. There are many tools available online that create CSS
sprites from separate images. One of them is http://www.csssprites.com/.
Although it works in most of the situations, this method has its drawbacks -
in the rare cases in which users have turned off images in their browsers but
retained CSS, a big empty hole will appear in the page where we expect our
images to be placed. The links are still there and clickable, but nothing visually
appears.
Combined Scripts and Stylesheets
Most of the websites, nowadays, are built using JavaScript and CSS. There are
two ways of using them, either inline, or from external script and stylesheet files.
Generally, using the latter approach is better for performance, but since there is
a trend of breaking the code into many small files (the idea of modularization), it
might lead to bigger response time, since additional HTTP requests are needed.
The solution is using two combined files, one for all the scripts, and the other,
for all the stylesheets. One website that provides compared results for common
practices in building websites is http://stevesouders.com/hpws/rules.php.
The tests have proven that pages with the combined scripts loads 38% faster.
Use a Content Delivery Network
A content delivery network (CDN) is a collection of web servers distributed across
multiple locations to deliver content to users more efficiently. This efficiency is
typically discussed as a performance issue, but it can also result in cost savings.
When optimizing for performance, the server selected for delivering content to
a specific user is based on a measure of network proximity. For example, the
CDN may choose the server with the fewest network hops or the server with the
quickest response time. Other benefits include backups, caching, and the ability
5. to absorb traffic spikes better. Examples of CDNs include Akamai Technologies,
Limelight Networks, SAVVIS, and Panther Express. Smaller and noncommercial
web sites might not be able to afford the cost of these CDN services, but there
are several free CDN services available:
1. Globule (http://www.globule.org) - an Apache module developed at Vrije
Universiteit in Amsterdam;
2. CoDeeN (http://codeen.cs.princeton.edu) - developed at Princeton Uni-
versity on top of PlanetLab;
3. CoralCDN (http://www.coralcdn.org) - developed at New York Univer-
sity.
Add an Expires Header
When a user visits a Web page, the browser downloads and caches the page’s
resources. The next time the user visits the page, the browser checks to see if any
of the resources can be served from its cache, avoiding time-consuming HTTP
requests. The browser bases its decision on the resource’s expiration date. If
there is an expiration date, and that date is in the future, then the resource is
read from disk. If there is no expiration date, or that date is in the past, the
browser issues a HTTP request. Web developers can avoid the delay caused by
the new request by specifying an explicit expiration date in the future.
The HTTP specification define this header as ”the date/time after which the
response is considered stale.” It is sent in the HTTP response and it looks as
following:
Expires: Thu, 1 Jan 2015 20:00:00 GMT
If this header is returned for an image in a page, the browser uses the cached
image on subsequent page views, reducing the number of HTTP requests by one.
Compress components
Another way of reducing the response time is by reducing the size of the HTTP
response, which means that fewer packets need to travel from the server to the
client. Many Web servers and Web-hosting services enable compression of HTML
documents by default, but compression shouldn’t stop there. Developers should
also compress other types of text responses, such as scripts, stylesheets, XML,
and JSON, among others. GNU zip (gzip) is the most popular compression
technique. It typically reduces data sizes by 70 percent. Web clients indicate
support for compression with the Accept-Encoding header in the HTTP request:
Accept-Encoding: gzip, deflate
If the web server sees this header in the request, it may compress the response
using one of the methods listed by the client.The web server notifies the web
client of this via the Content-Encoding header in the response:
Content-Encoding: gzip
6. Correct Approach to Dealing with CSS and Scripts
Progressive rendering is an expression used for the pages that load preogressively
- the browser displayes the content as soon as it is available, even if it not the
entire content. This is especially important for pages with a lot of content and
for users on slower Internet connections. The importance of giving users visual
feedback is summarized by Jakob Nielson:
Progress indicators have three main advantages: They reassure the user that
the system has not crashed but is working on his or her problem; they indicate
approximately how long the user can be expected to wait, thus allowing the user to
do other activities during long waits; and they finally provide something for the
user to look at, thus making the wait less painful. This latter advantage should
not be underestimated and is one reason for recommending a graphic progress
bar instead of just stating the expected remaining time in numbers.
Put Stylesheets at the Top
Stylesheets inform the browser how to format elements in the page. If stylesheets
are included lower in the page, the broswer might face the situation when it has
available content, but it does not know how to render it. Browser deal with this
problem differently:
Internet Explorer delays rendering elements in the page until all stylesheets are
downloaded. This causes the page to appear blank for a longer period of time,
however, giving users the impression that the page is slow.
Firefox renders page elements and redraws them later if the stylesheet changes
the initial formatting. This causes elements in the page to ”flash” when they’re
redrawn, which is disruptive to the user.
The best answer is to avoid including stylesheets lower in the page and instead
load them in the HEAD of the document.
Put Scripts at the Bottom
External scripts (mainly JavScript files) have a bigger impact on performance
than do other resources, for two reasons. First, once a browser starts downloading
a script it won’t start any other parallel downloads. Second, the browser won’t
render any elements below a script until the script has finished downloading.
Both of these impacts are felt when scripts are placed near the top of the page,
such as in the HEAD section. Other resources in the page (such as images)
are delayed from being downloaded and elements in the page that already exist
(such as the HTML text in the document itself) aren’t displayed until the earlier
scripts are done. Moving scripts lower in the page avoids these problems.
7. Avoid CSS expressions
CSS expressions are a way to set CSS properties dynamically. They enable setting
a style’s property based on the result of executing JavaScript code embedded
within the style declaration. The issue with CSS expressions is that they are
evaluated more frequently than one might expectpotentially thousands of times
during a single page load. If the JavaScript code is inefficient, it can cause the
page to load more slowly.
Not all the browser support all the CSS properties, and one solution for obtaining
the same rendering in all of them is using CSS expressions. The following example
ensures that a page width is always at least 600 pixels, using an expression that
Internet Explorer respects and a static setting honored by other browsers:
width: expression(document.body.clientWidth < 600 ?
"600px" : "auto" );
min-width: 600px;
CSS expressions are re-evaluated when the page changes, such as when it is
resized.This ensures that as the user resizes his browser, the width is adjusted
appropriately.The frequency with which CSS expressions are evaluated is what
makes them work, but it is also what makes CSS expressions bad for perfor-
mance.
8. The Benefits of Ajax
Ajax(Asynchronous JavaScript and XML) is a cross-platform set of technologies
that allows developers to create web pages that behave more interactively, like
applications. It uses a combination of Cascading Style Sheets (CSS), XHTML,
JavaScript, and some textual datausually XML or JavaScript Object Notation
(JSON) to exchange data asynchronously. This allows sectional page updates
in response to user input, reducing server transfers (and resultant wait times)
to a minimum. The goal of Ajax is to increase conversion rates through a faster,
more user-friendly web experience. Unfortunately, unoptimized Ajax can cause
performance lags, the appearance of application fragility, and user confusion.
The improved communication power of the Ajax pattern is caused primarily
by the XMLHttpRequest object(XHR). The object is natively supported in
browsers such as Firefox, Opera, and Safari, and was initially supported as an
ActiveX control under Internet Explorer 6.x and earlier. In IE 7.x, XHRs are
natively supported, but the ActiveX solution is also available.
The following JavaScript function contains the first step of sending an Ajax
request:
function createXHR( ){
// Firefox, Opera, Safari, IE 7.x
try { return new XMLHttpRequest();
} catch(e) {}
// IE 6.x and earlier
try { return new ActiveXObject("Msxml2.XMLHTTP.6.0");
} catch (e) {}
try { return new ActiveXObject("Msxml2.XMLHTTP.3.0");
} catch (e) {}
try { return new ActiveXObject("Msxml2.XMLHTTP");
} catch (e) {}
try { return new ActiveXObject("Microsoft.XMLHTTP");
} catch (e) {}
// No XHR support
return null;
}
A simple call creates an XMLHttpRequest object:
var xhr = createXHR( );
The open() method of the XHR object is used to begin forming the request,
specifying the HTTP method, URI, and a boolean value that indicates whether
the request should be synchronous(false) or asynchronous(true).
9. xhr.open("GET","test.php",true);
Summarized, the advantages of Ajax over classical web-based applications in-
clude:
1. Asynchronous calls Ajax allows for the ability to make asynchronous calls
to a web server. This allows the client browser to avoid waiting for all data
to arrive before allowing the user to act once more.
2. Minimal data transfer By not performing a full postback and sending all
form data to the server, network utilization is minimized and quicker oper-
ations occur. In sites and locations with restricted pipes for data transfer,
this can greatly improve network performance.
3. Limited processing on the server Along with the fact that only the necessary
data is sent to the server, the server is not required to process all form
elements. By sending only the necessary data, there is limited processing on
the server.
4. ResponsivenessBecause Ajax applications are asynchronous on the client,
they are perceived to be very responsive.
5. Context With a full postback, users may lose the context of where they
are. Users may be at the bottom of a page, hit the Submit button, and be
redirected back to the top of the page. With Ajax there is no full postback.
Clicking the Submit button in an application that uses Ajax will allow users
to maintain their location. The user state is maintained, and the users are
no longer required to scroll down to the location they were at before clicking
Submit.
Inspite of all the obvious benefits, one should not abuse of Ajax calls. Although
most requests should be made asynchronously so that the user can continue work-
ing without the browser locking up as it is waiting for a response, synchronous
data transfer is not always an inappropriate choice. The reality is that some
requests must, in fact, be made synchronously because of dependency concerns.
JavaScript Optimization
JavaScript brings all the Ajax technologies together and optimizing the .js code
might be a key action in improving the website performance. Despite this real-
ity, JavaScript has a reasonable claim to being the world’s most misunderstood
programming language. While often considered a toy, beneath its simplicity lie
some powerful language features. Deeper knowledge of this technology is an im-
portant skill for any web developer.
JavaSript has the ability to supply objects that control a web browser and its
Document Object Model (DOM). For example, client-side extensions allow an
application to place elements on an HTML form and respond to user events such
as mouse clicks, form input, and page navigation.
Web browsers can interpret client-side JavaScript statements embedded in an
HTML page. When the browser (or client) requests such a page, the server sends
10. the full content of the document, including HTML and JavaScript statements,
over the network to the client. The browser reads the page from top to bottom,
displaying the results of the HTML and executing JavaScript statements as they
are encountered.
Since most of the user response time is spent on dealing with the content, op-
timizing JavaScript is very important. There are a few simple rules that can
significantly improve the performance:
1. Remove the comments - most of the time, they just increase the file size.
2. Remove the whitespaces. For example, instead of writing this:
var str = "JavaScript is " +
x +
" times more fun than HTML ";
you can write this:
var str="JavaScript is "+x+" times more fun than HTML";
3. Use JavaScript shortand -
x + 1
should be replaced with
x++
And the code:
var isGreater;
if (x > 10) {
isGreater = true;
}
else {
isGreater = false;
}
can become this:
var isGreater = (x > 10) ? true : false;
4. Use string constant macros - if a message needs to be displayed often, declare
a string variable containing that message.
5. Remap built-in objects - the file size can be reduced by renaming the built-in
objects, such as Window, Document, Navigator. For example,
alert(window.navigator.appName);
alert(window.navigator.appVersion);
alert(window.navigator.userAgent);
could be rewritten as follows:
w=window;n=w.navigator;a=alert;
a(n.appName);
a(n.appVersion);
6. Lazy-load the code - many JavScript libraries support the ”lazy-loading”
concept - the code is loaded only when necessary.
11. Web Site Performance Monitoring and Testing
Continuous monitoring is critical to ensuring that the website and web-based
applications are available and performing with acceptable response times.
There are many tools for monitoring and testing websites, such as Firebug,
Y!Slow - for Firefox, or Selenium, that is supported in many browsers.
Firebug
Firebug is a revolutionary Firefox extension that helps web developers and de-
signers test and inspect front-end code.
It includes a powerful JavaScript debugger that alows pausing the execution at
any time. Using the JavaScript profiler, one can measure performance and find
bottlenecks fast. The command line is one of the oldest tools in the programming
toolbox. Firebug includes a command line for JavaScript and provides power-
ful logging functions for all the Ajax request traffic, also allowing developers
to inspect the responses. The tool includes inspectors for HTML and CSS that
provide all the related information about the page’s elements. Users can alter
the HTML and CSS and the effects are seen instantly.
Firebug is free and open source.
Y!Slow and JSLint
Y!Slow is a Yahoo product that analyzes web pages and finds out why they are
slow, based on some rules for high performance. It is integrated with Firebug
and its features include a performance report card, HTTP/HTML summary, the
list of components in the page and some integrated tools, like JSLint. JSLint is
a code quality tool for JavaScript. It takes a source text and scans it. If it finds a
problem, it returns a message describing the problem and an approximate loca-
tion within the source. The problem is not necessarily a syntax error, although
it often is. JSLint looks at some style conventions as well as structural problems.
It does not prove that the program is correct, but it can and does reveal the
code’s problems.
Y!Slow completes FireBug functionality to make Firefox an unbeatable web de-
velopment tool.
Selenium
Selenium is a high quality open source test automation tool for web application
testing. Selenium runs in Internet Explorer, Mozilla and Firefox on Windows,
Linux, and Macintosh, Safari on the Mac. It includes an IDE for Selenium test
scripts, which are portable and can also be run from JUNit. For example, test
12. scripts written using Selenium IDE in Firefox on Windows can run on Firefox
in Mac or Linux, without changing any code. Selenium tests run directly in
browsers and so matches the end-user experience closely.
Selenium provides a rich set of testing functions specifically designed to the
needs of testing of a web application. These operations are highly flexible, allow-
ing many options for locating UI elements and comparing expected test results
against actual application behavior.
References
1. Andrew B. King, ”Website Optimization”, O’Reilly Media, 2008.
2. Steve Souders, ”High Performance Web Sites”, O’Reilly Media, 2007.
3. Douglas Crockford, ”JavaScript - The Good Parts”, O’Reilly Media, 2008.
4. Jakob Nielson, ”Response Times: The Three Important Limits”, http://www.
useit.com/papers/responsetime.html.
5. Douglas Crockford, ”The World’s Most Misunderstood Programming Language”,
http://javascript.crockford.com/javascript.html.
6. Yahoo! Developer Network Blog,
http://developer.yahoo.net/blog/archives/2007/03/high_performance.html.