function isValidEmail($email, $checkDNS = false)
{
$valid = (
function_exists('filter_var') and filter_var($email, FILTER_VALIDATE_EMAIL)
) || (
strlen($email) <= 320
and preg_match_all(
'/^(?!(?:(?:\\x22?\\x5C[\\x00-\\x7E]\\x22?)|(?:\\x22?[^\\x5C\\x22]\\x22?))'.
'{255,})(?!(?:(?:\\x22?\\x5C[\\x00-\\x7E]\\x22?)|(?:\\x22?[^\\x5C\\x22]\\x22?))'.
'{65,}@)(?:(?:[\\x21\\x23-\\x27\\x2A\\x2B\\x2D\\x2F-\\x39\\x3D\\x3F\\x5E-\\x7E]+)|'.
'(?:\\x22(?:[\\x01-\\x08\\x0B\\x0C\\x0E-\\x1F\\x21\\x23-\\x5B\\x5D-\\x7F]|(?:\\x5C[\\x00-\\x7F]))*\\x22))'.
'(?:\\.(?:(?:[\\x21\\x23-\\x27\\x2A\\x2B\\x2D\\x2F-\\x39\\x3D\\x3F\\x5E-\\x7E]+)|'.
'(?:\\x22(?:[\\x01-\\x08\\x0B\\x0C\\x0E-\\x1F\\x21\\x23-\\x5B\\x5D-\\x7F]|'.
'(?:\\x5C[\\x00-\\x7F]))*\\x22)))*@(?:(?:(?!.*[^.]{64,})'.
'(?:(?:(?:xn--)?[a-z0-9]+(?:-+[a-z0-9]+)*\\.){1,126})'.'{1,}'.
'(?:(?:[a-z][a-z0-9]*)|(?:(?:xn--)[a-z0-9]+))(?:-+[a-z0-9]+)*)|'.
'(?:\\[(?:(?:IPv6:(?:(?:[a-f0-9]{1,4}(?::[a-f0-9]{1,4}){7})|'.
'(?:(?!(?:.*[a-f0-9][:\\]]){7,})(?:[a-f0-9]{1,4}(?::[a-f0-9]{1,4}){0,5})?::'.
'(?:[a-f0-9]{1,4}(?::[a-f0-9]{1,4}){0,5})?)))|'.
'(?:(?:IPv6:(?:(?:[a-f0-9]{1,4}(?::[a-f0-9]{1,4}){5}:)|'.
'(?:(?!(?:.*[a-f0-9]:){5,})'.'(?:[a-f0-9]{1,4}(?::[a-f0-9]{1,4}){0,3})?::'.
'(?:[a-f0-9]{1,4}(?::[a-f0-9]{1,4}){0,3}:)?)))?(?:(?:25[0-5])|'.
'(?:2[0-4][0-9])|(?:1[0-9]{2})|(?:[1-9]?[0-9]))(?:\\.(?:(?:25[0-5])|'.
'(?:2[0-4][0-9])|(?:1[0-9]{2})|(?:[1-9]?[0-9]))){3}))\\]))$/iD',
$email)
);
if( $valid )
{
if( $checkDNS && ($domain = end(explode('@',$email, 2))) )
{
return checkdnsrr($domain . '.', 'MX');
}
return true;
}
return false;
}
//-----------------------------------------------------------------
var_dump(isValidEmail('nechtan@tagon8inc.com', true));
// bool(true)
filter_var()
函数的PHP版本中,name2@domain.com
都可以正常工作。证明链接:http://3v4l.org/joLvm - Brad