JavaScript Libraries (Kings of Code)

JavaScript Libraries John Resig - May 2008 http://ejohn.org/ http://twitter.com/jeresig/

Question: How do you want to write JavaScript?

1) Plug-and-Play • Drop in a “calendar widget” or “tabbed navigation” • Little, to no, JavaScript experience required. • Just customize some options and go. • No ﬂexibility.

2) Some Assembly Required • Write common utilities • Click a link, load a page via Ajax • Build a dynamic menu • Creating interactive forms • Use pre-made code to distance yourself from browser bugs. • Flexible, until you hit a browser bug.

3) Down-and-Dirty • Write all JavaScript code from scratch • Deal, directly, with browser bugs • Quirksmode is your lifeline • Excessively ﬂexible, to the point of hinderance.

What we’ve just seen... • Widgets • Libraries • Raw JavaScript

Why use a library? • Makes JavaScript bearable • Gets the job done fast • Simpliﬁes cross-browser support • Sort of like C stdlib - no one just codes all of C by hand

What kind of libraries exist? Open Source Commercial Atlas Client/ AjaxCFC Backbase for Server Qcodo Struts Prototype Browser jQuery Backbase Only Yahoo UI SmartClient Dojo

Open Source Libraries Browser Only Client/Server Scriptaculous Task AjaxCFC moo.fx Speciﬁc Qcodo Open Rico Prototype General jQuery Ruby on Rails Purpose Yahoo UI CakePHP Dojo

Why these libraries?

Developer Survey jQuery Prototype Yahoo UI Dojo 14% 32% 22% 32% http://ajaxian.com/archives/nitobi-survey-results-on-ajax- development

Google Trends jQuery Prototype Dojo Yahoo UI http://google.com/trends?q=prototype+javascript%2C+jquery+javascript%2C+yui+javascript%2C+dojo+javascript&ctab=0&geo=all&date=all&sort=0

Others • MooTools • ExtJS • Ajax.NET

The Libraries

Prototype

Prototype: Overview • Started early 2005 by Sam Stephenson • Incredibly popular, tied with Ruby on Rails’ popularity • Development backed by 37 Signals

Prototype: Focus • Improving the usability of the JavaScript language • Big emphasis on adding in ‘missing’ JavaScript features • Clean structure, clean objects and ‘classes’

Prototype: Details • Code quality is fantastic, great features • All animations (and interactions) are in Scriptaculous • Updated frequently • Looking at Prototype 1.6.0.2

jQuery

jQuery: Overview • Released January 2006 by John Resig • Rapid rise in popularity • Many developers across the globe

jQuery: Focus • Improving the interaction between JavaScript and HTML • Finding elements then performing actions • Highly-effective, short, code

jQuery: Details • Core features are limited to DOM, Events, Effects, Ajax • Other features can be added in via plugins • Looking at jQuery 1.2.6

Yahoo! UI

YUI: Overview • Released Feb 2006 by Yahoo! • Maintained and ﬁnanced internally • Attempt to standardize internal JavaScript • Say ‘hi’ to Nate Koechley!

YUI: Focus • Exposing, and solving, common methodologies • Looking for common idioms (Drag-and- Drop, Calendar, Auto-Complete) • Looking at Yahoo UI 2.5.1

Dojo

Dojo: Overview • Started early 2005 by Alex Russell + Co. • Large development community • Lots of corporate backing (IBM, AOL) • Big code base, tons of features

Dojo: Focus • Building complete web applications • A package heirarchy, e.g.: dojo.addClass( ... ) • Focus has transcended into widgets (Dijit) • Huge number of features • Today we’re looking at Dojo 1.1.1

What should a library have?

Code Base • Core Functionality • DOM • Events • Ajax • Animations • User Interface Widgets

Development • Good Architecture • Open Licensing • Wide Browser Support • Small File Size

Project • Development Team (Open, Funded) • Code in SVN / Bug Tracker • Good Unit Test Coverage

Documentation • Full API Coverage • Plenty of Tutorials • Some Books • Wide variety of Demos

Community • Active Mailing List / Forum • Support and Training • Popularity

Code Base • Core Functionality • DOM • Events • Ajax • Animations • User Interface Widgets

Core Functionality • Bare minimum needed to make a dynamic “Ajax” web site: • DOM (Traversal and Manipulation) • Events • Ajax • Animations

DOM • Traversal • Using CSS selectors to locate elements • Modiﬁcation • Create/remove/modify elements • Having a DOM builder is important

DOM Traversal • Prototype: $$(“table > tr”) • jQuery: $(“div > p:nth-child(odd)”) • Dojo: dojo.query(“table tr:nth-child(even)”) • Yahoo UI: YAHOO.util.Selector.query('div p')

DOM Modiﬁcation • Prototype: Insertion.Bottom(“list”,”<li>Another item</li>”); • jQuery: $(“#li”).append(“<li>An item</li>”); • Dojo and Yahoo UI have weak support - no DOM building capabilities, basic property modiﬁcation

Events • Support for simple event binding/removal • Support for custom events is essential • Prototype: Event.observe(“button”,”click”, function(){ alert(“Thanks for the click!”); }); • jQuery: $(“div”).click(function(){ alert(“div clicked”); });

Events (cont.) • Yahoo UI: YAHOO.util.Event.addEventListener(“list”, “click”, function(){ alert(“List Clicked”); }); • Dojo: dojo.connect(dojo.byId(\"mylink\"), \"click\", function(){ alert(“Link clicked”); });

Custom Events • $(“#list”).bind(“drag”, function(){ $(this).addClass(“dragged”); }); • $(“#test”).trigger(“drag”);

Ajax • Request and load remote documents • Prototype: new Ajax.Request(“test.html”, { method: “GET”, onComplete: function(res){ $(‘results’).innerHTML = res.responseText; } }); • jQuery: $(“#results”).load(“test.html”);

Ajax (cont.) • Yahoo UI YAHOO.util.Connect.asyncRequest( 'GET', “test.html”, function(data){ YAHOO.util.Dom.id(“results”).innerHTML = data; } ); • Dojo dojo.io.bind({ url: \"test.html\", method: \"get\", mimetype: \"text/html\", load: function(type, data) { dojo.byId(“results”).innerHTML = data; } });

Ajax (cont.) • jQuery is only one capable of doing DOM traversing over XML • jQuery.get(“test.xml”, function(xml){ $(“user”, xml).each(function(){ $(“<li/>”).text( $(this).text() ) .appendTo(“#userlist”); }); });

Animations • Simple animations (hide/show/toggle) • Provide elegant transitions • No animations in Prototype Core (see Scriptaculous, instead) • jQuery: $(“#menu”).slideDown(“slow”);

Animations (cont.) • Yahoo UI: new YAHOO.util.Anim(“list”, { width: { from: 10, to: 100 } }, 1, YAHOO.util.Easing.easeOut ); • Dojo: dojo.fadeOut({ node: dojo.byId(“list”), duration: 500 });

Core Feature Summary DOM Events Anim. Ajax Prototype X X - X jQuery X X X X Yahoo UI / X X X Dojo / X X X

User Interface Widgets • Difﬁcult to implement components, made easy • Commonly used, save duplication • Some common components: Drag & Drop, Tree, Grid, Modal Dialog, Tabbed Pane, Menu / Toolbar, Datepicker, Slider

User Interface Packages • Only looking at ofﬁcially-supported code: • Prototype has Scriptaculous • jQuery has jQuery UI • Dojo has Dijit • Included in Yahoo UI

Drag & Drop • Drag an item from one location and drop in an other • Supported by all libraries

Tree • A navigable hierarchy (like a folder/ﬁle explorer) • In Dojo and Yahoo UI

Grid • An advanced table (resizable, editable, easily navigable) • In Dojo and Yahoo UI

Modal Dialog • Display conﬁned content (usually drag & droppable) and conﬁrmation dialogs • In Dojo,Yahoo UI, and jQuery

Tabbed Pane • Multiple panes of content navigable by a series of tabs • In Dojo,Yahoo UI, and jQuery

Menu / Toolbar • A list of navigable items (with sub-menus) • In Dojo and Yahoo UI

Datepicker • An input for selecting a date (or a range of dates) • In Dojo,Yahoo UI, and jQuery

Slider • A draggable input for entering a general, numerical, value • In all libraries

Tons More! • Color Picker (Dojo,YUI) • Layout (Dojo,YUI) • Auto Complete (Dojo, Proto,YUI) • Selectables (Proto, jQuery) • Accordion (Dojo, jQuery) • WYSIWYG (Dojo,YUI)

Themeing • A consistent look-and-feel for widgets • jQuery,Yahoo UI, and Dojo provide themeing capabilities • jQuery’s and Yahoo UI’s are documented

Accessibility • Taking in to consideration points from ARIA (Accessible Rich Internet Applications) • Dojo is taking a solid lead, here • jQuery received funding and is working on ARIA integration to jQuery UI

Development • Good Architecture • Open Licensing • Wide Browser Support • Small File Size

Architecture • Bottom Up (Prototype, jQuery) vs. Top Down (Dojo,Yahoo UI) • jQuery, Dojo, and Yahoo UI all use a single namespace • Prototype extends native objects (high likelihood of inter-library conﬂict) • jQuery is extensible with plugins • Dojo uses a package system

Licensing • All use liberal licenses (“Keep my name on the ﬁle, don’t sue me.”) • MIT: Prototype, jQuery • BSD: Yahoo UI, Dojo

Browser Support • Everyone supports: IE 6+, Firefox 2+, Safari 2+, Opera 9+ • Note: • Most are in the process of dropping support for Safari 2

File Size • Serving your JavaScript miniﬁed + Gzipped • Optimal level of compression and speed • Core ﬁle size (in KB): 35.00 26.25 17.50 8.75 0 Prototype jQuery Yahoo UI Dojo

Project • Development Team (Open, Funded) • Code in SVN / Bug Tracker • Good Unit Test Coverage

Development Team • Prototype, jQuery, and Dojo all have open development (anyone can contribute) • jQuery,Yahoo UI, and Dojo all have paid, full-time, developers working on the code • All have paid, part-time, developers

SVN / Bug Tracker • Prototype, jQuery, and Dojo all have code in a public SVN repositories • Yahoo UI’s development is private and is limited to Yahoo employees • They’re working to ﬁx this! • All libraries have a public bug tracker

Unit Tests • All libraries have some automated unit tests • jQuery,Yahoo UI, and Dojo all have public unit test URLs • jQuery and Dojo have tests that can run in Rhino

Documentation • Full API Coverage • Plenty of Tutorials • Some Books • Wide variety of Demos

API Documentation • Prototype, jQuery, and Yahoo UI all have full coverage • jQuery provides runnable examples with each API item • Dojo’s coverage is improving - work in progress (dojocampus.org, etc.)

Tutorials • All libraries provide some tutorials • jQuery,Yahoo UI, and Dojo have screencasts/presentations • Prototype: 6 • jQuery: 118 (English) • Yahoo UI: Numerous (each component has at least one) • Dojo: 24

Books • Prototype: • Prototype and Scriptaculous in Action (Manning) • Prototype and Scriptaculous (Pragmatic) • jQuery: • Learning jQuery (Packt) • jQuery Reference Guide (Packt) • Yahoo UI: • Learning the Yahoo UI Library (Packt) • Dojo: 3 books coming in 2008

Demos • Yahoo UI provides a considerable number of live demos and examples for all features • jQuery provides live examples and a few demo applications • Dojo provides demo applications for their widgets

Community • Active Mailing List / Forum • Support and Training • Popularity

Mailing List / Forum • Prototype, jQuery, and Yahoo UI have mailing lists • Prototype: 23 posts/day • jQuery: 76 posts/day • Yahoo UI: 56 posts/day • Dojo has an active forum

Support and Training • Dojo provides paid support and training (via Sitepen) • jQuery provides paid jQuery UI support and training (via Liferay)

Popularity • Who uses what: • Prototype: Apple, ESPN, CNN, Fox News • jQuery: Google, Amazon, Digg, NBC, Intel • Yahoo:Yahoo, LinkedIn, Target, Slashdot • Dojo: IBM, AOL, Mapquest, Bloglines

More Information • Prototype: http://prototypejs.org/ • jQuery: http://jquery.com/ • Yahoo UI: http://developer.yahoo.com/yui/ • Dojo: http://dojotoolkit.org/

JavaScript Libraries (Kings of Code)

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