jQuery

jQuery

File:Jquerylogo.png
Developer(s)	jQuery Team
Stable release	1.4.1 / January 25, 2010
Written in	JavaScript
Development status	Active
Type	Web application framework
License	Dual license: GPL and MIT
Website	http://jquery.com/

jQuery is a lightweight cross-browser JavaScript library that emphasizes interaction between JavaScript and HTML. It was released in January 2006 at BarCamp NYC by John Resig. Used at about 20% of the 10,000 biggest websites, jQuery is the most popular JavaScript library in use today.

jQuery is free, open source software, dual-licensed under the MIT License and the GNU General Public License, Version 2. jQuery's syntax is designed to make it easier to navigate a document, select DOM elements, create animations, handle events, and develop Ajax applications. jQuery also provides capabilities for developers to create plugins on top of the JavaScript library. Providing this option, developers are able to create abstractions for low-level interaction and animation, advanced effects and high-level, theme-able widgets. This contributes to the creation of powerful and dynamic web pages.

Microsoft and Nokia have announced plans to bundle jQuery on their platforms, Microsoft adopting it initially within Visual Studio for use within Microsoft's ASP.NET AJAX framework and ASP.NET MVC Framework whilst Nokia will integrate it into their Web Run-Time platform.

Features

jQuery contains the following features:

• DOM element selections using the cross-browser open source selector engine Sizzle, a spin-off out of the jQuery project
• DOM traversal and modification (including support for CSS 1-3)
• Events
• CSS manipulation
• Effects and animations
• Ajax
• Extensibility through plugins
• Utilities - such as browser version and the each function.

Use

jQuery usually exists as a single JavaScript file, containing all the common DOM, Event, Effects, and Ajax functions. It can be included within a web page using the following mark-up:

<script type="text/javascript" src="jQuery.js"></script>

jQuery can also be accessed, loaded, and run just as JavaScript has always been:

jQuery can also be loaded using the Google AJAX Libraries API with the following mark-up:

<script type="text/javascript" src="http://www.google.com/jsapi"></script>
<script>
google.load("jquery", "1.3.2");
</script>

Microsoft hosted jQuery on its AJAX CDN (Content delivery network) making it easy to add the support for jQuery library. CDN serves JavaScript libraries from one of thousands of geo-located edge-cache servers around the world hosted by Microsoft.

<script src="http://ajax.microsoft.com/ajax/jquery/jquery-1.3.2.min.js" type="text/javascript"></script>

jQuery has two styles of interaction:

• via the $ function, which is a factory method for the jQuery object. These functions, often called commands, are chainable; they each return the jQuery object
• via $.-prefixed functions. These are utility functions which do not work on the jQuery object per se.

A typical workflow for manipulation of multiple DOM nodes begins with the $ function being called with a CSS selector string, which results in the jQuery object referencing zero or more elements in the HTML page. This node set can be manipulated by applying instance methods to the jQuery object, or the nodes themselves can be manipulated. For example:

$("div.test").add("p.quote").addClass("blue").slideDown("slow");

...finds the union of all div tags with class attribute test and all p tags with CSS class attribute quote, adds the class attribute blue to each matched element, and then slides them down with an animation. The $ and add functions affect the matched set, while the addClass and slideDown affect the referenced nodes.

The methods prefixed with $. are convenience methods or affect global properties and behaviour. For example, the following is an example of the map function called each in jQuery:

$.each([1,2,3], function() {
  document.write(this + 1);
});

... writes the numbers 234 to the document.

It is possible to perform browser-independent Ajax queries using $.ajax and associated methods to load and manipulate remote data.

$.ajax({
  type: "POST",
  url: "some.php",
  data: "name=John&location=Boston",
  success: function(msg){
    alert( "Data Saved: " + msg );
  }
});

... will request some.php from the server with parameters name=John and location=Boston and when the request is finished successfully, the success function will be called to alert the user.

Release history

Release date	Version number	Additional notes
August 26, 2006	1.0	First Stable Release
August 31, 2006	1.0.1
October 9, 2006	1.0.2
October 27, 2006	1.0.3
December 12, 2006	1.0.4	Last 1.0 bug fix
January 14, 2007	1.1
January 22, 2007	1.1.1
February 27, 2007	1.1.2
July 1, 2007	1.1.3
July 5, 2007	1.1.3.1
August 24, 2007	1.1.4
September 10, 2007	1.2
September 16, 2007	1.2.1
January 15, 2008	1.2.2
February 8, 2008	1.2.3
May 19, 2008	1.2.4
May 21, 2008	1.2.5	Fix for bad build of 1.2.4
May 24, 2008	1.2.6
January 14, 2009	1.3	Sizzle Selector Engine introduced into core
January 21, 2009	1.3.1
February 20, 2009	1.3.2
January 14, 2010	1.4
January 25, 2010	1.4.1

High Profile Sites using JQuery

jQuery is used at 2142, or 21.42%, of the 10,000 most popular websites (as ranked by Alexa Internet) according to BackendBattles.com

• msn.com
• twitter.com
• microsoft.com
• imdb.com
• espn.go.com

See also

• Comparison of JavaScript frameworks

References

• Taft, Darryl K. (2006-08-30). "jQuery Eases JavaScript, AJAX Development". eWeek. http://www.eweek.com/c/a/Application-Development/jQuery-Eases-JavaScript-AJAX-Development/. Retrieved 2009-05-04. 
• Krill, Paul (2006-08-31). "JavaScript, .Net developers aided in separate projects". InfoWorld. http://www.infoworld.com/d/developer-world/javascript-net-developers-aided-in-separate-projects-531. Retrieved 2009-05-04. 
• John Resig (speaker). (2007-04-13) (Yahoo! Video). Advancing JavaScript with Libraries (Part 1). YUI Theater. http://video.yahoo.com/watch/410472/2391234. Retrieved 2009-05-04. 
• John Resig (speaker). (2007-04-13) (Yahoo! Video). Advancing JavaScript with Libraries (Part 2). YUI Theater. http://video.yahoo.com/watch/412541/2395771. Retrieved 2009-05-04. 

Bibliography

• Holzner, Steven (July 30, 2009). jQuery: Visual QuickStart Guide (1st ed.). Peachpit Press. pp. 240. ISBN 978-0321647498. http://www.peachpit.com/store/product.aspx?isbn=0321647491. 
• York, Richard (May 4, 2009). Beginning JavaScript and CSS Development with jQuery (1st ed.). Wrox Press. pp. 560. ISBN 978-0470227794. http://www.wrox.com/WileyCDA/WroxTitle/Beginning-JavaScript-and-CSS-Development-with-jQuery.productCd-0470227796.html. 
• Chaffer, Jonathan; Swedberg, Karl (February 13, 2009). Learning jQuery 1.3 (1st ed.). Packt Publishing. pp. 444. ISBN 978-1847196705. http://www.packtpub.com/learning-jquery-1.3/book/mid/1802090m1d2r. 
• Chaffer, Jonathan; Swedberg, Karl (July 30, 2007). jQuery Reference Guide: A Comprehensive Exploration of the Popular JavaScript Library (1st ed.). Packt Publishing. pp. 268. ISBN 978-1847193810. http://www.packtpub.com/jquery-reference-guide-Open-Source. 
• Chaffer, Jonathon; Swedberg, Karl (July 7, 2007). Learning jQuery: Better Interaction Design and Web Development with Simple JavaScript Techniques (1st ed.). Packt Publishing. pp. 380. ISBN 978-1847192509. http://www.packtpub.com/jQuery/book. 
• Bibeault, Bear; Katz, Yehuda (February 7, 2008). jQuery in Action (1st ed.). Manning Publications Co.. pp. 376. ISBN 978-1933988351. http://www.manning.com/bibeault/. 
• Heilmann, Christian (July 14, 2006). Beginning JavaScript with DOM Scripting and Ajax (1st ed.). Apress. pp. 512. ISBN 978-1590596807. http://www.apress.com/book/view/1590596803. 
• Darie, Cristian; Filip Chereches-Tosa, Mihai Bucicia (March 10, 2006). AJAX and PHP: Building Responsive Web Applications (1st ed.). Packt Publishing. pp. 284. ISBN 978-1904811824. http://www.packtpub.com/ajax-php/book. 
• Heilmann, Christian; Mark Norman Francis (April 18, 2007). Web Development Solutions (1st ed.). Friends of Ed. pp. 280. ISBN 978-1590598061. http://www.friendsofed.com/book.html?isbn=9781590598061. 

External links

• jquery organization
• Official website
• jQuery Plugin Development A set of articles that explain building custom jQuery plugins.
• Quick Reference Api
• Simplify Ajax development with jQuery
• Dmitri Gaskin (speaker). (2008-04-03) (YouTube). jQuery. Google Tech Talks. http://www.youtube.com/watch?v=8mwKq7_JlS8. Retrieved 2009-05-04. 
• OOP in jQuery: a small article outlining problems using OOP with jQuery, with several workarounds.
• JQuery intro for a C# developer: blog spot that explains jquery using analogy to LINQ.