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：

<?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;

}

?>

希望本文所述对大家的php程序设计有所帮助。