Getting Started

To use the Selector Utility, include the following source files in your web page with the <script> tag:

<!-- Dependencies -->
<script src="http://yui.yahooapis.com/2.9.0/build/yahoo/yahoo-min.js"></script>
 
<!-- Source file -->
<script src="http://yui.yahooapis.com/2.9.0/build/selector/selector-min.js"></script>
 

<!-- Dependencies -->
<script src="http://yui.yahooapis.com/2.9.0/build/yahoo/yahoo-min.js"></script>
 
<!-- Source file -->
<script src="http://yui.yahooapis.com/2.9.0/build/selector/selector-min.js"></script>
 

Basic Usage

The Selector API is most commonly used to retrieve a collection of elements that match a given CSS selector. This is done using the query() method.

var nodes = YAHOO.util.Selector.query('div p');
 

var nodes = YAHOO.util.Selector.query('div p');
 

In this example, the array of nodes returned contains all HTMLElements that are of type P that have a DIV ancestor.

The query() method can take an optional root node from which to begin the search and a boolean third argument that, if true, will cause the Selector Utility to return only the first node that matches the selector. For example, the following query will return only the first P element with a DIV ancestor that is a descendent of the element with an ID attribute of foo:

var node = YAHOO.util.Selector.query('div p', 'foo', true);
 

var node = YAHOO.util.Selector.query('div p', 'foo', true);
 

Using Selector

This section describes several common uses of Selector. It contains these subsections:

• Using Selector to Attach Event Listeners
• Testing a Node
• Filtering Nodes
• Using Attribute Operators
• Using Pseudo-classes

Using Selector to Attach Event Listeners

The query method can be useful for attaching events to a number of elements.

var handleClick = function(e) {
    alert('click');
};
var nodes = YAHOO.util.Selector.query('li a');
YAHOO.util.Event.on(nodes, 'click', handleClick);
 

var handleClick = function(e) {
    alert('click');
};
var nodes = YAHOO.util.Selector.query('li a');
YAHOO.util.Event.on(nodes, 'click', handleClick);
 

The above example listens for clicks on all anchors that are descendants of an LI element. The handleClick function is invoked when any of of the nodes are clicked.

Testing a Node

Another useful method that Selector provides is test(), which accepts a node and a simple selector, and returns true or false, depending on whether or not the node matches the provided selector.

var node = document.getElementById('foo');
alert(YAHOO.util.Selector.test(node, 'div.bar'));
 

var node = document.getElementById('foo');
alert(YAHOO.util.Selector.test(node, 'div.bar'));
 

The above example will alert true if the node is of type DIV and has a class of bar, otherwise it will alert false.

Filtering Nodes

Selector also provides a means for filtering a set of nodes based on a simple selector.

var candidates = document.getElementsByTagName('a');
var nodes = YAHOO.util.Selector.filter(candidates, '[href]');
 

var candidates = document.getElementsByTagName('a');
var nodes = YAHOO.util.Selector.filter(candidates, '[href]');
 

The above example filters the candidate anchor elements and returns only those that have the href attribute set.

Using Attribute Operators

Selector implements CSS3 Attribute Selectors, which includes a number of powerful operators for use in testing attributes.

For example, say you want to collect all input elements whose names begin with "yui". This is a job for the "starts with" ("^=") operator:

var nodes = YAHOO.util.Selector.query('input[name^=yui]');
 

var nodes = YAHOO.util.Selector.query('input[name^=yui]');
 

The above example returns only input elements whose name attribute begins with "yui". See the CSS3 Specification for additional examples of attribute operators.

Using Pseudo-classes

Selector also implements most CSS3 Pseudo-classes, allowing for additional matching based on information that can not be expressed using simple selectors.

For example, you may want only the first child item of an unordered list:

var nodes = YAHOO.util.Selector.query('ul li:first-child');
 

var nodes = YAHOO.util.Selector.query('ul li:first-child');
 

The not pseudo-class can be used if you want to match elements that DO NOT meet certain criteria:

var nodes = YAHOO.util.Selector.query('input:not([type=button])');
 

var nodes = YAHOO.util.Selector.query('input:not([type=button])');
 

The above example returns only input elements that are NOT of type BUTTON. See the CSS3 Specification for additional examples of pseudo-classes.

YUI on Mobile: Using Selector Utility with "A-Grade" Mobile Browsers

The Selector Utility is fully supported on Apple's iPhone and the Nokia N-Series browsers; you can expect functional parity between Selector Utility on these devices as compared to the supported A-Grade browsers.

Support & Community

The YUI Library and related topics are discussed on the on the YUILibrary.com forums.

Also be sure to check out YUIBlog for updates and articles about the YUI Library written by the library's developers.

Filing Bugs & Feature Requests

The YUI Library's public bug tracking and feature request repositories are located on the YUILibrary.com site. Before filing new feature requests or bug reports, please review our reporting guidelines.