<?     
if(!isset($_GET['r']))     
{     
echo "<script language=\"JavaScript\">     
<!--      
document.location=\"$PHP_SELF?r=1&width=\"+screen.width+\"&Height=\"+screen.height;     
//-->     
</script>";     
}     
else {         

// Code to be displayed if resolutoin is detected     
     if(isset($_GET['width']) && isset($_GET['Height'])) {     
               // Resolution  detected     
     }     
     else {     
               // Resolution not detected     
     }     
}     

?>