===== Syntax =====

<code php>
boolean isemail(string $email)
</code>

//(PHP 4, PHP 5)//

^ $email | Email to test if it is vaid or not |
^ RETURNS | True result if the argument contains a valid e-mail address, false otherwise. |

===== What it Does =====

Tests an expression to see if it contains a valid e-mail address or not.  This function uses an advanced regular expression (POSIX version) to check the string argument.

===== Function Declaration =====

<code php>
function isemail($email) {
    return preg_match('|^[_a-z0-9-]+(\.[_a-z0-9-]+)*@[a-z0-9-]+(\.[a-z0-9-]{2,})+$|i', $email);
}
</code>