jQuery Delegate Function Example
Let's have a closer look at the jQuery .delegate() function.
Description
The .delegate() function also provides a way of attaching event handlers to new elements, like was saw in the .live() function demo. You may find that .delegate() is faster than .live() because the latter searches the entire document namespace for the elements as opposed to a single document context. Also, you can specify a jQuery selector to match mutiple events based on a specified set of root elements. Lets have a look at an example of the delegate jQuery function in action. Further Reading »
Demo
Demo: Delegating events to child elements of a root element.
The demo area is the root element (orange border) with coloured span child elements which have a hover event attached.
Download
The download package includes all the inline HTML, CSS, JavaScript, jQuery and images required for the .delegate() function demo so you can try it yourself and change as you please.
Code
<!-- Copyright 2011 jQuery4u.com -->
<!DOCTYPE html>
<html>
<title>jQuery Function Demo - jQuery4u.com</title>
<head>
<script src="http://www.jquery4u.com/function-demos/js/jquery-1.6.4.min.js"></script>
<script src="http://www.jquery4u.com/scripts/function-demos-script.js"></script>
<script type="text/javascript">
var JQFUNCS =
{
runFunc:
{
/* ------------------------------ delegate Demo ------------------------------ */
"delegate":
{
run: function(id)
{
$('#'+id).css({"display":"inline-block"});
var frequency = .3;
for (var i = 0; i < 32; ++i)
{
var frequency = .3;
for (var i = 0; i < 45; ++i)
{
r = Math.sin(frequency*i + 0) * 127 + 128;
g = Math.sin(frequency*i + 2) * 127 + 128;
b = Math.sin(frequency*i + 4) * 127 + 128;
$('#'+id).append('<span class="smallcolor" style="background-color:'+JQFUNCS.RGB2Color(r,g,b)+';"></span>');
}
}
$('#'+id).delegate('span', 'hover', function(e)
{
$(this).toggleClass("whitebg");
})
},
reset: function(id)
{
$('#'+id).empty().hide();
}
}
},
RGB2Color: function(r,g,b)
{
return '#' + this.byte2Hex(r) + this.byte2Hex(g) + this.byte2Hex(b);
},
byte2Hex: function(n)
{
var nybHexString = "0123456789ABCDEF";
return String(nybHexString.substr((n >> 4) & 0x0F,1)) + nybHexString.substr(n & 0x0F,1);
}
}
</script>
<style type="text/css" media="screen">
.whitebg {background-color: white !important; width:30px!important;}
.smallcolor { float:left;width:10px;height:30px; }
</style>
</head>
<body>
<p class="example">Demo: Delegating events to child elements of a root element.</p>
<p>The demo area is the root element (orange border) with coloured span child elements which have a hover event attached.</p>
<p><a href="#" id="delegate-demobtn" class="demobtn btn actionr">Run Demo</a> <a href="#" id="delegate-codebtn" class="codebtn btn actionr">View Code</a> <a href="#" id="delegate-resetbtn" class="resetbtn btn actionr" style="display: none;">Reset</a></p>
<div class="demoarea" id="delegate" style="border:1px solid orange;padding:20px;"></div>
</body>
</html>
<!-- Copyright 2011 jQuery4u.com -->