验证邮件地址，经常用，记下来

function checkEmail(input) {

var emailPattern = /^/w+((-/w+)|(/./w+))*/@[A-Za-z0-9]+((/.|-)[A-Za-z0-9]+)*/.[A-Za-z0-9]+$/;

//var nubmer = document.getElementById(input).value;

if (emailPattern.test(input)==false) { //alert("非法的Email地址！"); return false; }

else { //alert("正确的Email地址！") return true; } }

==== 调用

if(document.getElementById("email").value!=""&&checkEmail(document.getElementById("email").value)==false){
alert('邮件格式错误');
document.getElementById("email").value="";
document.getElementById("email").focus();
return false;
}