PHP Regular Expression Validation example code for an email

Source: Internet
Author: User
Tags php regular expression
The regular expression (regular expression) describes a pattern of string matching that can be used to check whether a string contains a seed string, replace a matched substring, or remove a substring from a string that matches a certain condition. This article mainly introduces the PHP regular verification email method, involving PHP regular expression validation of the relevant skills, the need for friends can refer to the following . Specific as follows:

<?phpfunction Validateemail ($email) {$isValid = true; $atIndex = Strrpos ($email, "@"); if (Is_bool ($atIndex) &&amp  ;! $atIndex) {$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 both consecutive dots $isValid = false; } else if (!preg_match ('/^[a-za-z0-9\\-\\.  +$/', $domain)) {//character not valid on domain part $isValid = false;  } else if (Preg_match ('/\\.\\./', $domain)) {//Domain part has both consecutive dots $isValid = false; } else if (!preg_maTCH ('/^ (\\\\.| [a-za-z0-9!#%& ' _=\\/$\ ' *+?^{}|~.-]) +$/', Str_replace ("\\\\", "", $local))) {//character not valid on local part unless//local-is quoted if (!p Reg_match ('/^ ' (\\\\ "|[   ^ "]) +" $/", Str_replace (" \\\\ "," ", $local))) {$isValid = false; }} if ($isValid &&! ( CHECKDNSRR ($domain, "MX") | |  CHECKDNSRR ($domain, "A"))) {//Domain not found in DNS $isValid = false; }} return $isValid;}? >

Contact Us

The content source of this page is from Internet, which doesn't represent Alibaba Cloud's opinion; products and services mentioned on that page don't have any relationship with Alibaba Cloud. If the content of the page makes you feel confusing, please write us an email, we will handle the problem within 5 days after receiving your email.

If you find any instances of plagiarism from the community, please send an email to: info-contact@alibabacloud.com and provide relevant evidence. A staff member will contact you within 5 working days.

A Free Trial That Lets You Build Big!

Start building with 50+ products and up to 12 months usage for Elastic Compute Service

  • Sales Support

    1 on 1 presale consultation

  • After-Sales Support

    24/7 Technical Support 6 Free Tickets per Quarter Faster Response

  • Alibaba Cloud offers highly flexible support services tailored to meet your exact needs.