JavaScript实现表单输入框高亮聚焦效果

<!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">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>当前输入框高亮显示</title>
<style> 
body,form,h2,p,input{margin:0;padding:0;}
body{color:#4f4f4f;font:14px/1.5 \5fae\8f6f\96c5\9ed1;}
form{width:400px;background:#fef4eb;border:2px solid #f60;padding-bottom:10px;overflow:hidden;zoom:1;margin:10px auto;}
form h2{color:#fe791e;font-size:16px;background:#ffebd7;border-bottom:2px solid #f60;padding:5px 10px;}
form p{float:left;clear:both;width:100%;height:31px;margin-top:10px;line-height:31px;}
form label,form input{float:left;}
form label{width:100px;height:31px;text-align:right;}
form input{border:0;font-family:\5fae\8f6f\96c5\9ed1;background:url(input.png) no-repeat;}
form .f-text,form .f-text-high{width:203px;height:31px;padding-left:5px;line-height:31px;}
form .f-text-high{background-position:0 -31px;}
form .f-btn{color:#fff;width:104px;height:31px;cursor:pointer;font-size:16px;background:#f60;line-height:31px;border-radius:5px;}
</style>
<script type="text/javascript"> 
window.onload = function ()
{
 var aInput = document.getElementsByTagName("input");
 var i = 0;
 for (i = 0; i < aInput.length - 1; i++)
 {
  aInput[i].onfocus = function ()
  {
   this.className = "f-text-high"
  };
  aInput[i].onblur = function ()
  {
   this.className = "f-text"
  } 
 }
};
</script>
</head>
<body>
<form>
 <h2>用户登录</h2>
 <p><label>用户名：</label><input class="f-text" type="text" /></p>
 <p><label>密码：</label><input class="f-text" type="password" /></p>
 <p><label></label><input class="f-btn" type="button" value="登 录" /></p>
</form>
</body>
</html>