回车键的老问题？？？

<HTML><HEAD><TITLE> New Document </TITLE>
<meta http-equiv="Content-Language" content="zh-cn"><meta http-equiv="Content-Type" content="text/html; charset=gb2312">
<META NAME="Generator" CONTENT="EditPlus">
<META NAME="Author" CONTENT="">
<META NAME="Keywords" CONTENT="">
<META NAME="Description" CONTENT="">
<SCRIPT LANGUAGE="JavaScript">
<!--
function JumpToNextBox(){
var dom=document.all;
for(i=0;i<dom.length;i++){
if(dom[i].tagName=="INPUT"&&event.keyCode==13){
if(dom[i].type.toLowerCase()=="text")
event.keyCode=9;
}
}
}
//-->
</SCRIPT>
</HEAD>
<BODY onkeydown="JumpToNextBox()">
<form>
姓名：<input name="name"><br/>
年龄：<input name="age"><br/>
住址：<input name="addr"><br/>
<input type="submit" value="submit">
</form>
</BODY>
</HTML>