To detect an iPad or an iPhone in PHP use following function

function is_ipad_or_iphone(){
    if((preg_match("/iPad/",$_SERVER['HTTP_USER_AGENT']) or preg_match("/iPhone/",$_SERVER['HTTP_USER_AGENT'])) and preg_match("/Mobile/",$_SERVER['HTTP_USER_AGENT']))
        return true;
    else
        return false;
}