以下代码加入HTML的<body>区：
<script language="javascript">
<!-- Begin
function chk(email, formname)
{
invalid = "";
if (!email)
invalid = "请输入您的Email地址。";
else {
if ( (email.indexOf("@") == -1) || (email.indexOf(".") == -1) )
invalid += "\n\nEmail地址不合法。应当包含'@'和'.'；例如('.com')。请检查后再递交。";
if (email.indexOf("your email here") > -1)
invalid += "\n\nEmail地址不合法，请检测您的Email地址，在域名内应当包含'@'和'.'；例如('.com')。";
if (email.indexOf("\\") > -1)
invalid += "\n\nEmail地址不合法，含有非法字符(\\)。";
if (email.indexOf("/") > -1)
invalid += "\n\nEmail地址不合法，含有非法字符(/)。";
if (email.indexOf("'") > -1)
invalid += "\n\nEmail地址不合法，含有非法字符(')。";
if (email.indexOf("!") > -1)
invalid += "\n\nEmail地址不合法，含有非法字符(!)。";
if ( (email.indexOf(",") > -1) || (email.indexOf(";") > -1) )
invalid += "\n\n只输入一个Email地址，不要含有分号和逗号。";
if (email.indexOf("?subject") > -1)
invalid += "\n\n不要加入'?subject=...'。";
}
if (invalid == "")
{
return true;
}
else
{
alert("输入的Email可能包含错误：" + invalid);
return false;
}
}
// End -->
</script>
<form method="post" name="myform" action="submit.asp" onSubmit="return chk(document.myform.email.value)">
<div align="center">
<input type="text" name="email" value="your email here">
<input type="submit" name="Submit" value="Submit">
</div>
</form>
