function IsPostcode($postcode) {     $postcode = strtoupper(str_replace(' ','',$postcode));     if(preg_match("/^[A-Z]{1,2}[0-9]{2,3}[A-Z]{2}$/",$postcode) || preg_match("/^[A-Z]{1,2}[0-9]{1}[A-Z]{1}[0-9]{1}[A-Z]{2}$/",$postcode) || preg_match("/^GIR0[A-Z]{2}$/",$postcode))     {         return true;     }     else     {         return false;     } }