<html>
<head>
<script type="text/javascript" src="../jquery/jquery.js" tppabs="http://www.w3school.com.cn/jquery/jquery.js"></script>
<script type="text/javascript">
$(document).ready(function(){
$("button").click(function(){
$("div").fadeTo("slow",0.25);
});
});
</script>
</head>

<body>
<div id="test" style="background:yellow;width:300px;height:300px">
<button type="button">Click to Fade</button>
</div>

</body>

</html>