请教框架问题~~~在线等待

a.htm
<FRAMESET ROWS="50,25,25,0" >
<FRAME SRC="1.htm" NAME="frame1">
<FRAME SRC="2.htm" NAME="frame2">
<FRAME SRC="3.htm" NAME="frame3">
<FRAME SRC="4.htm" NAME="frame4">
</FRAMESET>4.htm
<SCRIPT LANGUAGE="JavaScript">
<!--
function refreshFrame()
{
var x = 5000;
alert(parent.frame1.location.href + "\n" + parent.frame2.location.href );
parent.frame1.location.reload();
parent.frame2.location.reload();
window.setTimeout("refreshFrame()", x);
}
refreshFrame();
//-->
</SCRIPT>
:_)