<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8"/>
<title>moon</title>
<style type="text/css">
#moon{
display:block;
width:100px;
height:100px;
background-repeat:no-repeat;
background-image:url(moon.jpg);
}
#moon:hover{
background-position: -100px 0px;
}

</style>
</head>
<body>
<a href="" id="moon"></a>
</body>
</html>