In this case it is coded for a button image; using jquery for browser compatibility very much the same way as the html canvas fire animation was created last week.
<style>
#button {
background-image:url(strip.jpg);
width:250px;
height:150px;
background-position: -1px 0px;
}
</style>
<div id="button">
</div>
<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.4.2/jquery.js">
</script>
<script>
var left = 0;
var direction = -1;
setInterval(function(){
left+=direction;
$('#button').css('background-position', left+' 0px');
if (left < 250-1442) {direction = 1;}
// note image width 1442 pixels, button width 250 pixels,
// negative left is how many pixels
// are cropped off on the left side.
if (left > -1) {direction = -1;}
},50);
</script>
