<form name=form1><span   onclick="aa()">   
 <input type="radio" name="ischanged" value="1" >
<input type="radio" name="ischanged" value="0"  checked>
</span> 
</form><script language="JavaScript">function aa(){  e  =  event.srcElement;  
  alert(e.value);}</script>
参考帖子:
http://expert.csdn.net/Expert/FAQ/FAQ_Index.asp?id=4806