Question

This sounds strange, but I’ve been using this function for quite a while now and “suddenly, from one day to the other” it does not filter some addresses in the right way anymore. However, I cannot see why…

function validate_email($email)
{
/*
(Name) Letters, Numbers, Dots, Hyphens and Underscores
(@ sign)
(Domain) (with possible subdomain(s) ).
Contains only letters, numbers, dots and hyphens (up to 255 characters)
(. sign)
(Extension) Letters only (up to 10 (can be increased in the future) characters)
*/

$regex = '/([a-z0-9_.-]+)'. # name

'@'. # at

'([a-z0-9.-]+){2,255}'. # domain & possibly subdomains

'.'. # period

'([a-z]+){2,10}/i'; # domain extension 

if($email == '') { 
    return false;
}
else {
$eregi = preg_replace($regex, '', $email);
}

return empty($eregi) ? true : false;
}

e.g. “some@gmail” will be shown as correct, etc so it seems sth happened with the tld – does anybody could tell me why?

Thank you very much in advance!

Answer 1

. means any character. You should escape it if you actually mean ‘dot’: \.

Your regex also has some other problems:

• No uppercases are allowed in your regex: [a-zA-Z0-9]
• No unicode characters are allowed in your regex (for example email addresses with é, ç, … etc)
• Some special characters such as + are in fact allowed in an email address
• …

I would keep the email validation very simple. Like check if there is a @ present and pretty much keep it at that. For if you really want to validate an email, the regex becomes gruesome.

Check this SO answer for a more detailed explanation.