BBCode::IsValidURL( $string,  $email_too = true )

function IsValidURL($string, $email_too = true) {
if (preg_match("/^
(?:https?|ftp):\\/\\/
(?:
(?:[a-zA-Z0-9](?:[a-zA-Z0-9-]*[a-zA-Z0-9])?\\.)+
[a-zA-Z0-9]
(?:[a-zA-Z0-9-]*[a-zA-Z0-9])?
|
\\[
(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\\.){3}
(?:
25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?|[a-zA-Z0-9-]*[a-zA-Z0-9]:
(?:[\\x01-\\x08\\x0B\\x0C\\x0E-\\x1F\\x21-\\x5A\\x53-\\x7F]
|\\\\[\\x01-\\x09\\x0B\\x0C\\x0E-\\x7F])+
)
\\]
)
(?::[0-9]{1,5})?
(?:[\\/\\?\\#][^\\n\\r]*)?
$/Dx", $string)) return true;
if (preg_match("/^[^:]+([\\/\\\\?#][^\\r\\n]*)?$/D", $string))
return true;
if ($email_too)
if (substr($string, 0, 7) == "mailto:")
return $this->IsValidEmail(substr($string, 7));
return false;
}