如何实现文本框特效？

就是当Focus时使用另一种样式?比如背景变成别的颜色，当LoseFocus时恢复。

要求用两种方法实现，一种是使用另外的Class一种是直接写BackGround-Color.

1<head>
2<style>   
3.focus{background-color:#ffffff}   
4.blur{background-color:#3366cc}   
5</style>
6</head>

1<body>
2<input onblur="style.backgroundColor='#3366cc'" onfocus="style.backgroundColor=''"/>
3<input onblur="className='blur'" onfocus="className='focus'"/>
4</body>

---------------------------------------------------------------

1<input onblur="style.color='Blue'" onfocus="style.color='Red'"/>

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1<input onblur="style.backgroundColor='Blue'" onfocus="style.backgroundColor='Red'"/>

 1<html>
 2<head>
 3<title>Script Encoder Sample Page</title>
 4<style>   
 5.input1{behavior:url("bg.htc")}   
 6</style>
 7</head>
 8<body>
 9<input class="input1"/>
10</body>
11</html>

bg.htc//同一目录

 1<public:component>
 2<public:attach event="onfocus" onevent="fos()"></public:attach>
 3<public:attach event="onblur" onevent="blu()"></public:attach>
 4<script>   
 5function fos(){   
 6style.backgroundColor='#ffffff'   
 7}   
 8function blu(){   
 9style.backgroundColor='#3366cc'   
10}   
11</script>
12</public:component>