PHP Verify mailbox and mailbox validation

A

Domain name is any combination of a specific character set, English letters, numbers, and "-" (that is, hyphens or minus signs) in each country's text, but neither the beginning nor the end can contain a "-", "-" that does not appear consecutively. The letters in the domain name are not case-insensitive. The domain name can be up to 60 bytes (including suffix. com,. NET,. org, and so on).
/^[a-z] ([a-z0-9]*[-_]?[ a-z0-9]+) *@ ([a-z0-9]*[-_]?[ a-z0-9]+) +[.] [A-z] {2,3} ([.] [A-z] {2})? $/i;
/content/I constitutes a case-insensitive regular expression

The code is as follows	Copy Code
$email = "tanklo_--vehy@yahoo.com.cn"; function Check_email ($email) { $pattern _test = "/([A-z0-9]*[-_.]? [a-z0-9]+) *@ ([a-z0-9]*[-_]?[ a-z0-9]+) +[.] [A-z] {2,3} ([.] [A-z] {2})? /I "; Return Preg_match ($pattern _test, $email); } echo Check_email ($email);

The above can only be simple to verify the message format, the following a more specific verification method.

How PHP Validates:

The code is as follows

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? PHP validation of mailbox format functions function Valid_email ($email) { We check that there ' s one @ symbol, and that's the lengths are right if (!ereg ("^[^@]{1,64}@[^@]{1,255}$", $email)) { Email invalid because wrong number of characters in one section, or wrong number of @ symbols. return false; } Split it into sections to make life easier $email _array = explode ("@", $email); $local _array = Explode (".", $email _array[0]); for ($i = 0; $i < sizeof ($local _array); $i + +) { if (!ereg ([a-za-z0-9!#$%& #038; ' *+/=?^_`{|} ~-][a-za-z0-9!#$%& #038; ' *+/=?^_`{|} ~.-]{0,63}) | ("[^(\|")] {0,62} ")) $", $local _array[$i])) { return false; } } if (!ereg ("^[?[ 0-9.]+]?$ ", $email _array[1])) {//Check if domain is IP. If not, it should be valid domain name $domain _array = Explode (".", $email _array[1]); if (sizeof ($domain _array) < 2) { return false; Not enough parts to domain } for ($i = 0; $i < sizeof ($domain _array); $i + +) { if (!ereg ("^" ([a-za-z0-9][a-za-z0-9-]{0,61}[a-za-z0-9]) | ( [a-za-z0-9]+)) $ ", $domain _array[$i])) { return false; } } } return true; } application Example if (!valid_email ($myeml)) { echo "<script>alert (' please enter a valid e-mail address '); location.href= ' Javascript:history.back () ' </ Script> "; Break } ?>

Accidentally found the CHECKDNSRR function where there is more exquisite examples, to share to everyone!

code is as follows

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< php Function Validate_email ($email) { $exp = ' ^[a-z ' 0-9]+ ([. _-][a-z ' 0-9]+) *@ ([a-z0-9]+ (. _-][a-z0-9]+)) +$ "; If (eregi ($exp, $email)) {//Validate the validity of the email format first with a regular expression if (CHECKDNSRR (Array_pop (Explode ("@", $email)), "MX") {// Then use CHECKDNSRR to verify the validity of the domain name portion of the email return true; } else{ return false; } }else{ return false; } ??