请问核对密码不一致的错误提示的代码！在线等！！

假设有这么个表单:
<form name="form1" id="form1" action="submit.asp" method="post">
<input name="pass1" id="pass1" type="password" value="" />
<input name="pass2" id="pass2" type="password" value="" />
<input name="submit" id="submit" type="submit" value="OK" />
</form>

JavaScript 方法：
把<form>那里改成：
<form id="form1" action="submit.asp" method="post" onSubmit="return checkPassword()">
再加上一个脚本：
<script language="JavaScript">
function checkPassword()
{
var f = document.getElementById("form1");
if(f.pass1.value == '' || f.pass2.value == '')
{
alert("Empty password!");
return false;