Republished with Permission - Original Article

jQuery is a lightweight open source JavaScript library (only 15kb in size) that in a relatively short span of time has become one of the most popular libraries on the web.

A big part of the appeal of jQuery is that it allows you to elegantly (and efficiently) find and manipulate HTML elements with minimum lines of code.  jQuery supports this via a nice "selector" API that allows developers to query for HTML elements, and then apply "commands" to them.  One of the characteristics of jQuery commands is that they can be "chained" together - so that the result of one command can feed into another.  jQuery also includes a built-in set of animation APIs that can be used as commands.  The combination allows you to do some really cool things with only a few keystrokes.

For example, the below JavaScript uses jQuery to find all <div> elements within a page that have a CSS class of "product", and then animate them to slowly disappear:

Figure 1

As another example, the JavaScript below uses jQuery to find a specific <table> on the page with an id of "datagrid1", then retrieves every other <tr> row within the datagrid, and sets those <tr> elements to have a CSS class of "even" - which could be used to alternate the background color of each row:

Figure 2

[Note: both of these samples were adapted from code snippets in the excellent jQuery in Action book]

Providing the ability to perform selection and animation operations like above is something that a lot of developers have asked us to add to ASP.NET AJAX, and this support was something we listed as a proposed feature in the ASP.NET AJAX Roadmap we published a few months ago.  As the team started to investigate building it, though, they quickly realized that the jQuery support for these scenarios is already excellent, and that there is a huge ecosystem and community built up around it already.  The jQuery library also works well on the same page with ASP.NET AJAX and the ASP.NET AJAX Control Toolkit.

Rather than duplicate functionality, we thought, wouldn't it be great to just use jQuery as-is, and add it as a standard, supported, library in VS/ASP.NET, and then focus our energy building new features that took advantage of it?  We sent mail the jQuery team to gauge their interest in this, and quickly heard back that they thought that it sounded like an interesting idea too.