鼠标点击span内文字改变其底色
有4个span内都有文字，现在我想点一个的时候，被点的那个背景色改变，点下一个的时候别的三个恢复本来的颜色

[解决办法]

HTML code

<script language="JavaScript"> var curObj = null;var preColor;onload = function(){    var a = document.getElementById("pad").getElementsByTagName("span");    for(var i=0;i<a.length;i++){        a(i).onclick = (function(obj){            return function(){                if(curObj!=null) curObj.style.backgroundColor = preColor;                preColor = obj.style.backgroundColor;                obj.style.backgroundColor = "#CCC";                curObj = obj;            }        })(a(i));    }}</script><div id="pad">    <span> 111 </span>    <span> 222 </span>    <span> 333 </span>    <span> 444 </span></div>