Email validation is something that is needed in a variety of situations, but I’ve always struggled to find a good one…. Well, here are 2!

The first is something I found online somewhere, and has been modified a little…

$email = '[email protected]';

if(preg_match("/^[_a-z0-9-]+(\.[_a-z0-9-]+)*@[a-z0-9-]+(\.[a-z0-9-]+)*(\.[a-z]{2,3})+$/i", $email)) {
    // All OK, do something
} 
else { 
    // Not OK, throw error
}

The second is from the legendary Mark Jackson, it requires PHP5 and in his words:

PHP actually has a built in function called filter_var which has an email validation flag in it but it will allow for any hostname (like mark@localhost) which I do not like so I have added another simple check to make sure it has a dot after the @ sign the function I use is:

function checkEmail($e,$bypassVal=false) {
    // ensure the email has a valid extension
    if(($bypassVal!==false)&&(is_array($bypassVal))&&(in_array($e,$bypassVal))) { return true; }
    if(strpos($e,'@')>=strrpos($e,'.')) { return false; }
    return (filter_var($e, FILTER_VALIDATE_EMAIL) && preg_match('/@.+\./', $e)) ? true : false;
}

The $bypassVal variable allows you to specify any email addresses (in an array format) which can can go through without validation – just in case you want to specify a particular string or email which can get through.

Examples
checkEmail(‘[email protected]’); // returns true
checkEmail(‘mark@localhost’); // returns false
checkEmail(‘mark@localhost’,array(‘mark@localhost’)); // returns true
checkEmail(‘__I_GET_THROUGH__’,array(‘mark@localhost’,'__I_GET_THROUGH__’)); // returns true