php中如何用正则表达式对email进行判断

Question

http://expert.csdn.net/Expert/TopicView2.asp?id=1889425&datebasetype=now

Answer 1

<?php
if(!eregi("^([a-z0-9_]|\\-|\\.)+@(([a-z0-9_]|\\-)+\\.)+[a-z]{2,4}$",$email))
die ("EMAIL输入错误!");
else echo OK;
?>

Answer 2

function chk_email($email) //核实emai是否正确
  {
      $result = eregi("^[_.0-9a-z-]+@([0-9a-z][0-9a-z-]+.)+[a-z]{2,3}$", $email);
  return $result;
  }

Answer 3

在js里是这么写<script>
function check(v)
{
emailStr=/^\s*([A-Za-z0-9_\-]+(\.\w+)*@(\w+\.)+\w{2,3})\s*$/;
if (emailStr.test(v))
alert('正确');
else
alert('不正确');}</script>
<input type=text id='txtEmail'><button onclick='check(document.all.txtEmail.value)'>检查</button>