Loading Images Below the Fold
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Sources of Intellectual Property Included in the YUI Library
YUI is issued by Yahoo! under the BSD license above. Below is a list of certain publicly available software that is the source of intellectual property in YUI, along with the licensing terms that pertain to thosesources of IP. This list is for informational purposes only and is not intended to represent an exhaustive list of third party contributions to the YUI.
* Douglas Crockford's JSON parsing and stringifying methods: In the JSON Utility, Douglas Crockford's JSON parsing and stringifying methods are adapted from work published at JSON.org. The adapted work is in the public domain.
* Robert Penner's animation-easing algorithms: In the Animation Utility, YUI makes use of Robert Penner's algorithms for easing.
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* Diego Perini's IEContentLoaded technique: The Event Utility employs a technique developed by Diego Perini and licensed under GPL. YUI's use of this technique is included under our BSD license with the author's permission.
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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
<html>
<head>
<meta http-equiv="content-type" content="text/html; charset=utf-8">
<title>Loading Images Below the Fold</title>
<style type="text/css">
/*margin and padding on body element
can introduce errors in determining
element position and are not recommended;
we turn them off as a foundation for YUI
CSS treatments. */
body {
margin:0;
padding:0;
}
</style>
<link rel="stylesheet" type="text/css" href="yui_2.7.0b-lib/fonts/fonts-min.css" />
<script type="text/javascript" src="yui_2.7.0b-lib/yahoo-dom-event/yahoo-dom-event.js"></script>
<script type="text/javascript" src="yui_2.7.0b-lib/imageloader/imageloader-min.js"></script>
<!--there is no custom header content for this example-->
</head>
<body class=" yui-skin-sam">
<h1>Loading Images Below the Fold</h1>
<div class="exampleIntro">
<p>Often pages will have a number of images below the fold, hidden from the user's view. These are prime candidates to load with the <a href="http://developer.yahoo.com/yui/imageloader/">ImageLoader Utility</a>.</p>
<p>All the images in this example belong to the same group, and all load immediately only if they appear above the fold of the page.</p>
</div>
<!--BEGIN SOURCE CODE FOR EXAMPLE -->
<style>
.everything .cont { border:1px solid #888; width:100px; margin:25px 50px; }
.everything .right { margin-left:300px; }
#img1Cont, #img5Cont { height:75px; }
#img2Cont { height:67px; }
#img3Cont { height:53px; }
#img4Cont { height:72px; }
</style>
<div class='everything' id='everything'>
<div class='cont' id='img1Cont'>
<img id='img1' />
</div>
<div class='cont right' id='img2Cont'>
<img id='img2' />
</div>
<div class='cont' id='img3Cont'>
<img id='img3' />
</div>
<div class='cont right' id='img4Cont'>
<img id='img4' />
</div>
<div class='cont' id='img5Cont'>
<img id='img5' />
</div>
</div>
<script>
var foldGroup = new YAHOO.util.ImageLoader.group(window, 'scroll');
foldGroup.registerSrcImage('img1', 'http://developer.yahoo.com/yui/docs/assets/examples/exampleimages/small/museum.jpg');
foldGroup.registerSrcImage('img2', 'http://developer.yahoo.com/yui/docs/assets/examples/exampleimages/small/uluru.jpg');
foldGroup.registerSrcImage('img3', 'http://developer.yahoo.com/yui/docs/assets/examples/exampleimages/small/katatjuta.jpg');
foldGroup.registerSrcImage('img4', 'http://developer.yahoo.com/yui/docs/assets/examples/exampleimages/small/morraine.jpg');
foldGroup.registerSrcImage('img5', 'http://developer.yahoo.com/yui/docs/assets/examples/exampleimages/small/japan.jpg');
foldGroup.foldConditional = true;
//foldGroup.addTrigger(window, 'resize');
foldGroup.name = 'fold_group';
/*
* This uncustomary wait before adding the resize trigger is done specifically to cater to IE for this example.
* In IE and with the Logger enabled, IE fires an immediate resize event while rendering the Logger module, consequently loading all the images in the example.
* This 200 ms delay allows IE to render the Logger without interference.
* In your code, you would add the resize trigger in a straightforward fashion, as is documented in the example.
*/
YAHOO.util.Event.addListener(window, 'load', function() { setTimeout("foldGroup.addTrigger(window, 'resize')", 200); });
</script>
<!--END SOURCE CODE FOR EXAMPLE -->
</body>
</html>
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