Using Ajax for deferred loading of items
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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>Using Ajax for deferred loading of items</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" />
<link rel="stylesheet" type="text/css" href="yui_2.7.0b-lib/carousel/assets/skins/sam/carousel.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/connection/connection-min.js"></script>
<script type="text/javascript" src="yui_2.7.0b-lib/element/element-min.js"></script>
<script type="text/javascript" src="yui_2.7.0b-lib/carousel/carousel-min.js"></script>
<!--begin custom header content for this example-->
<style type="text/css">
/* Style the spotlight container */
#spotlight {
border: 1px solid #ccc;
height: 240px;
margin: 10px auto;
padding: 1px;
text-align: center;
width: 240px;
}
#carousel {
margin: 0;
}
#container {
margin: 0 auto;
}
.yui-skin-sam .yui-carousel-nav ul,
.yui-skin-sam .yui-carousel-nav select {
display: none;
}
.yui-carousel-element li {
height: 75px;
width: 75px;
}
</style>
<!--end custom header content for this example-->
</head>
<body class=" yui-skin-sam">
<h1>Using Ajax for deferred loading of items</h1>
<div class="exampleIntro">
<p>
This example showcases the dynamic loading capabilities of the <a href="http://developer.yahoo.com/yui/carousel/">YUI Carousel Control</a>. The YUI Carousel Control exposes an event called <code>loadItems</code>. This
event is fired whenever the Carousel needs items to be loaded into it for
display. Subscribing to this event makes it easy to dynamically load
the next set of images.
</p>
</div>
<!--BEGIN SOURCE CODE FOR EXAMPLE -->
<!-- The Carousel container -->
<div id="container">
<ol id="carousel"></ol>
</div>
<!-- The spotlight container -->
<div id="spotlight"></div>
<script>
var curpos, items = [];
function getImageTag(img) {
return "<img src=\"" + img + "\" height=\"75\" width=\"75\">";
}
function getImages() {
var carousel = this;
YAHOO.util.Connect.asyncRequest("GET", "yui_2.7.0b-assets/carousel-assets/php/getimages.php?pos="+curpos,
{
success: function (o) {
var i = curpos,
j = 0,
r = eval('(' + o.responseText + ')');
curpos += r.length;
while (i < curpos) {
if (r[j]) {
carousel.addItem(getImageTag(r[j]));
} else {
break;
}
i++;
j++;
}
carousel.set("selectedItem", carousel.get("firstVisible"));
},
failure: function (o) {
alert("Ajax request failed!");
}
});
}
// Get the image link from within its (parent) container.
function getLargeImage(parent) {
var el = parent.firstChild;
while (el) { // walk through till as long as there's an element
if (el.nodeName.toUpperCase() == "IMG") { // found an image
// flickr uses "_s" suffix for small, and "_m" for big
// images respectively
return el.src.replace(/_s\.jpg$/, "_m.jpg");
}
el = el.nextSibling;
}
return "";
}
YAHOO.util.Event.onDOMReady(function (ev) {
var carousel, spotlight = YAHOO.util.Dom.get("spotlight");
carousel = new YAHOO.widget.Carousel("container", {
numItems: 17
});
YAHOO.util.Connect.asyncRequest("GET", "yui_2.7.0b-assets/carousel-assets/php/getimages.php", {
success: function (o) {
var i, r = eval('(' + o.responseText + ')');
curpos = r.length;
for (i = 0; i < curpos; i++) {
items.push(r[i]);
}
// check if the Carousel widget is available
if (typeof carousel != "undefined") {
for (i = 0; i < curpos; i++) {
// if so, shove the elements into it
carousel.addItem(getImageTag(items[i]));
}
carousel.set("selectedItem", 0);
items = [];
}
},
failure: function (o) {
alert("Ajax request failed!");
}
});
carousel.on("loadItems", function (o) {
// more items available?
getImages.call(this);
});
carousel.on("itemSelected", function (index) {
// item has the reference to the Carousel's item
var item = carousel.getElementForItem(index);
if (item) {
spotlight.innerHTML = "<img src=\""+getLargeImage(item)+"\">";
}
});
carousel.render();
carousel.show();
});
</script>
<!--END SOURCE CODE FOR EXAMPLE -->
</body>
</html>
<!-- presentbright.corp.yahoo.com uncompressed/chunked Thu Feb 19 10:53:08 PST 2009 -->
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