<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312" />
<title>用javascript判断用户输入email地址是否有效</title>
<script>
function checkEmail(){
var emailPattern = /^\w+((-\w+)|(\.\w+))*\@[A-Za-z0-9]+((\.|-)[A-Za-z0-9]+)*\.[A-Za-z0-9]+$/;
if (emailPattern.test(emails.value)==false)
alert("非法的Email地址！")
else
alert("正确的Email地址！")
}
</script>
</head>
<body>
<input id=emails><input type=button value=CheckEmail onclick=checkEmail()>
</body>
</html>
亦可以直接使用下面的代码，与上面的代码等效：
<meta http-equiv="Content-Type" content="text/html; charset=gb2312" />
<title>用javascript判断用户输入email地址是否有效</title>
<body>
<input type="text" name="mail"><input type="submit" onClick="alert(/^.+@.+\..+$/.test(mail.value))">
<!--严格一点是这样的：<input type="text" name="mail"><input type="submit" onClick="alert(/\w+@.+\..+$/.test(mail.value))">-->
</body>
</html>
