PHP正则验证Email的方法

本文实例讲述了PHP正则验证Email的方法。分享给大家供大家参考。具体如下：<?phpfunctio

本文实例讲述了PHP正则验证Email的方法。分享给大家供大家参考。具体如下：

<?php
function validateEmail($email)
{
 $isValid = true;
 $atIndex = strrpos($email, "@");
 if (is_bool($atIndex) && !$atIndex)
 {
 $isValid = false;
 }
 else
 {
 $domain = substr($email, $atIndex+1);
 $local = substr($email, 0, $atIndex);
 $localLen = strlen($local);
 $domainLen = strlen($domain);
 if ($localLen < 1 || $localLen > 64)
 {
 // local part length exceeded
 $isValid = false;
 }
 else if ($domainLen < 1 || $domainLen > 255)
 {
 // domain part length exceeded
 $isValid = false;
 }
 else if ($local[0] == '.' || $local[$localLen-1] == '.')
 {
 // local part starts or ends with '.'
 $isValid = false;
 }
 else if (preg_match('/\\.\\./', $local))
 {
 // local part has two consecutive dots
 $isValid = false;
 }
 else if (!preg_match('/^[A-Za-z0-9\\-\\.]+$/', $domain))
 {
 // character not valid in domain part
 $isValid = false;
 }
 else if (preg_match('/\\.\\./', $domain))
 {
 // domain part has two consecutive dots
 $isValid = false;
 }
 else if(!preg_match('/^(\\\\.|[A-Za-z0-9!#%&`_=\\/$\'*+?^{}|~.-])+$/', str_replace("\\\\","",$local)))
 {
 // character not valid in local part unless 
 // local part is quoted
 if (!preg_match('/^"(\\\\"|[^"])+"$/', str_replace("\\\\","",$local)))
 {
 $isValid = false;
 }
 }
 if ($isValid && !(checkdnsrr($domain,"MX") || checkdnsrr($domain,"A")))
 {
 // domain not found in DNS
 $isValid = false;
 }
 }
 return $isValid;
}
?>

PS：这里再为大家提供2款非常方便的正则表达式工具供大家参考使用：

JavaScript正则表达式在线测试工具： http://tools.jb51.net/regex/javascript

正则表达式在线生成工具： http://tools.jb51.net/regex/create_reg

希望本文所述对大家的php程序设计有所帮助。