点击Button修改该Button的背景图片?

<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312">
<title>无标题文档</title>
</head>
<body>
  <input type="button" name="Submit2" value="按钮" id="cc1"   onClick="this.style.backgroundImage='url(/pic/buttons.gif)';">
</form>
</body>
</html>