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jQuery Pocket Reference
book

jQuery Pocket Reference

by David Flanagan
December 2010
Intermediate to advanced content levelIntermediate to advanced
160 pages
3h 31m
English
O'Reilly Media, Inc.
Content preview from jQuery Pocket Reference

The jQuery() Function

The jQuery() function (a.k.a. $()) is the most important one in the jQuery library. It is heavily overloaded, however, and there are four different ways you can invoke it.

The first and most common way to invoke $() is to pass a CSS selector (a string) to it. When called this way, it returns the set of elements from the current document that match the selector. jQuery supports most of the CSS3 selector syntax, plus some extensions of its own. Complete details of the jQuery selector syntax are in jQuery Selectors. If you pass an element or a jQuery object as the second argument to $(), it returns only matching descendants of the specified element (or elements). This optional second argument value defines the starting point (or points) for the query and is often called the context.

The second way to invoke $() is to pass it an Element, Document, or Window object. Called like this, it simply wraps the element, document, or window in a jQuery object and returns that object, allowing you to use jQuery methods to manipulate the element rather than using raw DOM methods. It is common to see jQuery programs call $(document) or $(this), for example. jQuery objects can represent more than one element in a document, and you can also pass an array of elements to $(). In this case, the returned jQuery object represents the set of elements in your array.

The third way to invoke $() is to pass it a string of HTML text. When you do this, jQuery creates the HTML element (or elements) ...

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Publisher Resources

ISBN: 9781449398958Supplemental ContentErrata Page