<!DOCTYPE html>
<meta http-equiv="Content-Type" content="text/html;charset=utf-8">
<meta name="viewport" content="width=device-width,initial-scale=1.0,minimum-scale=1.0,maximum-scale=1.0,user-scalable=no">
<head>
</head>
<body>
<label>email:</label><input type="text" id="email"/>
<input type="button" value="验证" onclick="checkemail()" />
<span id="message"></span>
</body>
<script type="text/javascript">
function checkemail() {
var obj = document.getElementById("email");
if(obj.value != ""){
var str = obj.value;
if(str.indexOf("@") != -1 && str.indexOf(".") != -1){
var a = str.split("@");
if(a[0].length > 0){
if(a[1].length > 0){
var b = a[1].split(".");
if(b[0].length > 0){
if(b[1].length > 1){
document.getElementById("message").innerHTML = "<font color='green'>正确</font>";
}
else{
document.getElementById("message").innerHTML = "<font color='red'>错误，.后面必须要有至少2个字符！！！</font>";
}
}
else{
document.getElementById("message").innerHTML = "<font color='red'>错误，@和.之间必须要有至少1个字符！！！</font>";
}
}
else{
document.getElementById("message").innerHTML = "<font color='red'>错误，@后面必须要有至少1个字符！！！</font>";
}
}
else{
document.getElementById("message").innerHTML = "<font color='red'>错误，@前面必须要有至少1个字符！！！</font>";
}
}
else{
document.getElementById("message").innerHTML = "<font color='red'>错误，邮箱需要包含@和.字符！！！</font>";
}
}
}
</script>
</html>