PHP Regular Verification Email method _php Tips

The examples in this article describe the way PHP validates email. Share to everyone for your reference. as follows:

<?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 >) {//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 into 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: Here again for you to provide 2 very convenient regular expression tools for your reference to use:

JavaScript Regular expression online test tool:
Http://tools.jb51.net/regex/javascript

Regular expression online generation tool:
Http://tools.jb51.net/regex/create_reg

I hope this article will help you with your PHP program design.