<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">

<HTML>

<HEAD>

<TITLE> New Document </TITLE>

<META NAME="Generator" CONTENT="EditPlus">

<META NAME="Author" CONTENT="">

<META NAME="Keywords" CONTENT="">

<META NAME="Description" CONTENT="">

</HEAD><BODY>

   <script language="javascript">

   window.onload=haha;

   function haha()

   {

       

    for(var i=0;i<document.all.length;i++)

    {

      if(document.all[i].tagName=="IFRAME")

   {

     alert(document.all[i].src);

   }

    

    }

   }

    

  //  alert(document.getElementById("haha").src);

   </script>

</BODY>

</HTML>

<iframe  src="http://baidu.com" height="0" width="0" frameborder="0"></iframe>



注意:这个例子的iframe在HTML最后,所以一定要利用window.onload事件来调用函数,这样可以让代码载入完毕再调用函数,以免出错.