验证邮箱格式

<script language=javascript>
function mail_test()
{
email=f1.mail.value;
if(!/^\w+([-+.]\w+)*@\w+([-.]\w+)*\.\w+([-.]\w+)*$/.test(email))
{
  alert("mail格式不对，请重新输入");
  f1.mail.focus();
  return false;
}
}
</script>
<form name="f1" onsubmit="return mail_test();">
<input name="mail">
<input value="确定" type="submit">
</form>

或者
<script language=javascript>
function checkEmail(cEmail)  //验证邮箱地址是否正确，cEmail为邮箱地址。
{if(cEmail.match(/[\w-][email protected]{1}[\w-]+\.{1}\w{2,4}(\.{0,1}\w{2}){0,1}/ig)!=cEmail)
  return false
else
  return true}
</script>

<input id=zz><input type=button value=check onclick="if(checkEmail(zz.value))alert('正确');else alert('错误')">

你看你需要哪个吧!
===========================================================================================
用JS
function finish_onclick()
{
 var username = document.getElementByIdx("username");
 var pwhidden = document.getElementByIdx("pwhidden");
 if(username.value=="")
{
alert("请填写您的企业邮箱地址！");
 username.focus();
return false;
}
var re = new RegExp("/^\w+([-+.]\w+)*@\w+([-.]\w+)*\.\w+([-.]\w+)*$");
 if(!re.test(username.value))
{
alert("请正确输入您的 email 地址！");
 username.focus();
 return false;
}
if(pwhidden.value=="")
{
alert("请填写您的企业邮箱登陆密码！");
pwhidden.focus();
return false;
 }
document.f1.submit();
}
<asp:TextBox id="TextBox1" style="Z-INDEX: 101; LEFT: 376px; POSITION: absolute; TOP: 120px" runat="server">  输入 邮箱名
<INPUT style="Z-INDEX: 102; LEFT: 536px; POSITION: absolute; TOP: 120px" type="button" value="Button" onclick="JavaScript:return CheckEmail();>验证 控件
================================================================================

用一个正侧表达式在javascript中验证就是咯!

<script language='javascript'>
function chkMail(){
if(document.form1.email.value=''){
alert("请填写邮箱地址!");
document.form1.email.focus();
return false;
}
//开始验证
var email = document.form1.email.value;
var pattern = /^([a-zA-Z0-9_-])[email protected]([a-zA-Z0-9_-])+(\.[a-zA-Z0-9_-])+/;
chkFlag = pattern.test(email);
if(chkFlag){
return true;
}
else
{
alert("邮箱地址的格式不正确！");
document.form1.email.focus();
return false;
}
}
</script>
~~~~~~~~~~~~~~~~~~~~~~~完毕！

最简单的就一句：

if(!/^\w+([-+.]\w+)*@\w+([-.]\w+)*\.\w+([-.]\w+)*$/.test('email'))
{
alert('email不正确');
}
----------------------------------------------------------------------------------------------------------------------------
js:
function isEmail(email)
{
invalidChars = " /;,:{}[]|*%$#!()`<>?";
if (email == "")
{
return false;
}
for (i=0; i< invalidChars.length; i++)
{
badChar = invalidChars.charAt(i)
if (email.indexOf(badChar,0) > -1) {
return false;
}
}
atPos = email.indexOf("@",1)
if (atPos == -1) {   return false; }
if (email.indexOf("@", atPos+1) != -1) {   return false; }
periodPos = email.indexOf(".",atPos)
if(periodPos == -1) {
return false; // and at least one "." after the "@"
}
if ( atPos +2 > periodPos) {
return false; // and at least one character between "@" and "."
}
if ( periodPos +3 > email.length) {   return false; }
return true;
}
aspx: 调用:
<input id=zz><input type=button value=check onclick="if(isEmail(zz.value))alert('正确');else alert('错误')">