make a link that autofill an input in the linked page

[kh99]

Yeah, I can't follow all that. But there's a vbulletin function is_valid_email() that you can call. It just does this:

	return preg_match('#^[a-z0-9.!\#$%&\'*+-/=?^_`{|}~]+@([0-9.]+|([^\s\'"<>@,;]+\.+[a-z]{2,6}))$#si', $email);

But if what you're saying is that you have one input field named email, but it might be a user name, then I think you'd want to do this:

$vbulletin->input->clean_gpc('p', 'email', TYPE_STR);
$input_email = htmlspecialchars_uni($vbulletin->GPC['email']);
if (is_valid_email($input_email))
{
    if (empty($email))
    {
        $email = $input_email;
    }
}
else
{
    if (empty($username))
    {
        $username = $input_email;
    }
}

This probably bypasses the check for a valid/unused username, but that just means the user would just get an error after submitting.