Assignment 5: Evaluation Paper.doc
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  • 1. Erin Fahy Page 1 4/29/2010 LIS469 Ajax broke onto the web development and applications scene through Google Suggest (the suggested terms that appear under the basic Google search box as you type a search term), and then soon afterwards with Google Maps. Without delay web developers were raving about the new level of interactivity available through Ajax and quickly developed new features for sites like Flickr and Amazon. However, the original excitement around Ajax has now died down a bit and users are not as wowed around interactive features on their web pages, which secretly raised the level of web page interactive expectedness in users. They now carry their expectations into public libraries and universities, prompting digital initiative librarians to begin integrating Ajax functions into catalogs and library web sites. As an introduction, Ajax is not a language, a program, or even a way of encoding information in and of itself, but is rather a conceptual grouping of technologies and techniques that allows a browser to exchange data to and from a server virtually unnoticed, without a page reload. As an acronym, it stands for Asynchronous JavaScript and XML, and was originally developed as a short hand way of saying that a page uses these systems for backdoor data transmission to a web page1. The term now goes beyond this original definition to mean something almost entirely different. To be typically Ajax, an application does not need to use JavaScript or XML, nor does it even need to be asynchronous in its data gathering. What does makes an application strictly Ajax is to be based around a data exchange from browser to the server that is not apparent to the user; most commonly, this is accomplished using a JavaScript command called XMLHttprequest. Other common attributes of an Ajax function are 1 Garrett, J.J. (2005), Ajax: A New Approach to Web Applications, Adaptive Path, available at:
  • 2. Erin Fahy Page 2 4/29/2010 LIS469 centered on the dynamic appearance of a web site or page, its use of a Document Object Model (DOM)2, and the ability it gives a browser to request, transform, and store data from a server. An Ajax enabled web page utilizes recognizable and well-used components of a web page with which most developers are quite familiar. For example, XHTML and CSS are a must as far as the presentation and structure of the page. As for some of the less familiar components, Ajax uses the W3C recommended Document Object Model (DOM) for the updateable or dynamic portions of a page to be manipulated. DOM is required for JavaScript (another component of Ajax described later) to have the ability to inspect and alter the HTML of a page. Data to be transmitted back and forth from server to browser can come in an array of forms to include databases encoded in XML or JSON (JavaScript Object Notation), HTML, or in just plain text. The real “programming” in Ajax is within JavaScript, a lightweight scripting language primarily used in dynamic web pages. Through JavaScript, access is gained to objects within a web page and allows them to be manipulated. Coupled with the DOM, JavaScript can interact with particular portions of the page. Finally, the XMLHttpRequest, an application programming interface (API), is the back-door pathway that permits data exchange from server to browser and back. XMLHttpRequest is a somewhat misleading term because it does not require an XML data structure. Like Ajax, the term was made with XML in mind but its use has been broadened. Once the data is received from the server, it is loaded into the script itself as XML tagged data (if the data is in well-formed XML) or as plain text, which is then either presented to the user or 2 In short, through DOM scripting tags, text, or entire sections of a document are able to be manipulated on the fly. see
  • 3. Erin Fahy Page 3 4/29/2010 LIS469 stored for later use. Ajax is a perfect fit for use with a library’s online catalog or for digital libraries as a whole. Intelligently applied, Ajax is simply a streamlined and user-friendly way for a browser to interact with a database located on a server. This is also currently the main function of a library’s OPAC –to respond to user input, search the catalog database, and return the applicable information to the user. With Ajax, however a new level of interactivity is introduced to meet the norms of ‘Web 2.0.’ Unfortunately, traditionally set-up OPACs require a large amount of server-side processing to search through the many lists in a catalog database, which simultaneously slows down the experience for the user. Web pages enhanced with Ajax techniques greatly lessen the processing power needed on a server as it requests small chunks of data on a continual basis while it also creates a seemingly wait free experience for the user. This speed in processing and data return then ups the ante for what is available to display through an OPAC. Rich content display from other websites, RSS feeds, complex graphics, and basically whatever can be thought of to be stored in an XML or JSON database, can be more easily displayed through an Ajax system. Other advantages are focused around user experience, as recent user activity is able to be stored in script form for later use. As a basic example, say a library user locates a title through an OPAC that he/she would like to check out, but the title is only available through ILL. In a traditional setting, this request would involve copy/pasting from the library record into an ILL request form to be sent to the appropriate library personnel. However, with an Ajax enabled system, many more opportunities are available. One of the more complex ways would be to have a form generated directly from the current data
  • 4. Erin Fahy Page 4 4/29/2010 LIS469 displayed to the user through a “request” button or the like. However, that option requires a relatively skillful Ajax and JavaScript encoder and could potentially invite bugs into the system if not done with precision. A much easier and less complex way is to link the fields of the ILL request form with an XML file of titles in the catalog. As a user types the wanted title a list of suggestions is generated under the text field in response to the keystrokes. Once a wanted title is located, the system could populate the form based on the information in the XML file under that particular asset making the request easier on both the user and the system. Additionally, a recent study3 has shown that an Ajax formatted interface to a bibliographic database in Italy improves usability. Users surveyed regarding the interface claim it to be an excellent way to find information. Also, searching performed though the database by more than 2,000 patrons generated less than 10 requests for help. The conclusions of the study pointed towards the intuitiveness of Ajax designed sites. It is difficult to enumerate the shortcomings of Ajax in particular, in that it is an ever-changing and conceptual application -if problems arise with one particular suite of program, language, or data structure, a substitute can either be used or developed. That being said, JavaScript is indeed a scripting language that requires precision and skill to be performed correctly. As previously mentioned, trying to do too much with Ajax can introduce bugs and quirks across different platforms and browsers. For example, XMLHttpRequest can be in difficult when using IE, although there have been work- arounds developed for those issues. Additionally, careless JavaScript can cause undue strain on client-side processing resources. There are additional problems with a web page 3 Cavaleri, P. (2008). The use of AJAX in searching a bibliographic database: A case study of the Italian Biblioteche oggi database. Program, 42(3), 275-85. Retrieved April 12, 2009, from Library Lit & Inf Full Text database.
  • 5. Erin Fahy Page 5 4/29/2010 LIS469 being dynamic in total. The first problem is the inability to link to a static web page. As the Ajax enabled page is able to change in response to user input without reloading, the URI stays the same. An external link will help very little if a user intended to link to a page where information was already entered. This is also a problem in create valid bookmarks to manipulated pages. Similarly, printing becomes an issue as older printers send out information that comes from the server, not what a user sees on the screen. The commonly relied upon back button also becomes difficult in Ajax systems, as it cannot help in getting back to previous versions of the same page. Accessibility is another issue as screen readers and other disability focused software packages are incompatible for pages that change without reloading. Lastly, as more processing power becomes the responsibility of the browser, faster client-side connections alongside more powerful computers becomes a requirement for ease of use rather than a luxury. In the four years since the term was coined, Ajax has become even more of a conceptual application rather than an ordained technique. This is a testimony to the concept’s usefulness and adaptability, which in the coming years will develop preferences and best practices over how certain data is stored and transmitted to dynamic and interactive web pages. Particular data structures benefits and shortcomings –XML vs. JSON for example- will be further defined as they apply to Ajax applications. Currently XML is the most developed and most widely used of the database structure options, but that may change due to the shifting nature of Ajax. As a data gathering and displaying technique, Ajax holds many options for libraries in the years to come, and as digital asset librarians become more versed in web technologies and applications, Ajax (or perhaps something based on its foundation) might find a more permanent place in online catalogs
  • 6. Erin Fahy Page 6 4/29/2010 LIS469 or in digital libraries. Works Consulted: Cavaleri, P. (2008). The use of AJAX in searching a bibliographic database: A case study of the Italian Biblioteche oggi database. Program, 42(3), 275-85. Retrieved April 12, 2009, from Library Lit & Inf Full Text database. Clark, J. (2006). Building an Ajax Application from Scratch. Computers in Libraries, 26(10), 16-18, 20-2. Retrieved April 12, 2009, from Library Lit & Inf Full Text database. Clark, J. (2006). AJAX (Asynchronous JavaScript and XML): This Isn't the Web I'm Used To. Online (Weston, Conn.), 30(6), 31-4. Retrieved April 12, 2009, from Library Lit & Inf Full Text database. Garrett, J.J. (2005), Ajax: A New Approach to Web Applications, Adaptive Path, available at: West, J. (2006). Ajax: Not Just Another Acronym or Is It?. Searcher, 14(1), 13-15. Retrieved April 12, 2009, from Library Lit & Inf Full Text database. Wusterman, J., & O'hlceadha, P. (2006). Using Ajax to Empower Dynamic Searching. Information Technology and Libraries, 25(2), 57-64. Retrieved April 12, 2009, from Library Lit & Inf Full Text database.