方法1：
<html>
<head>
<title>Checking an email address - Version 01</title>
<script type="text/javascript" language="javascript">
<!-- //
function IsMatchingAddress(str){
var myRegExp = /[a-z0-9-]{1,30}@[a-z0-9-]{1,65}.[a-z]{3}/ ;
return myRegExp.test(str)
}
function TestGuess(){
var EmailAddr = "jbxue123@sina.com".toLowerCase();
alert(IsMatchingAddress(EmailAddr));
}
// -->
</script>
</head>
<body>
<h3>This page allows you to enter and check
an email address such as jbxue123@sina.com</h3>
<form>
<button type="Button" onclick="TestGuess()">
Click here to enter email address</button>
</form>
</body>
</html>
方法2：
<html>
<head>
<title>Checking an email address - Version 02</title>
<script type="text/javascript" language="javascript">
<!-- //
function IsMatchingAddress(str){
var myRegExp = /[a-z0-9-.]{1,30}@[a-z0-9-]{1,65}.(com|net|org|info|biz|([a-z]{2,3}.[a-z]{2}))/ ;
return myRegExp.test(str)
}
function TestGuess(){
var EmailAddr = "jbxue123@sina.com".toLowerCase();
alert(IsMatchingAddress(EmailAddr));
}
// -->
</script>
</head>
<body>
<h3>This page allows you to enter and check an email address
such as jbxue123@sina.com,</h3>
<form>
<button type="Button" onclick="TestGuess()">
Click here to enter email address</button>
</form>
</body>
</html>
方法3：
<html>
<head>
<title>E-mail Example</title>
<script type="text/javascript">
function isValidEmail(sText) {
var reEmail = /^(?:w+.?)*w+@(?:w+.)+w+$/;
return reEmail.test(sText);
}
function validate() {
var oInput1 = document.getElementById("txt1");
if (isValidEmail(oInput1.value)) {
alert("Valid");
} else {
alert("Invalid!");
}
}
</script>
</head>
<body>
<P>E-mail Address: <input type="text" id="txt1" /><br />
<input type="button" value="Validate" onclick="validate()" /></p>
</body>
</html>