 <!DOCTYPE html>
    <html>
     <head>
      <meta charset="utf-8">
       <script> 

        function setCookie(cname,cvalue,exdays) {
          var d = new Date();
          d.setTime(d.getTime()+(exdays*24*60*60*1000));
          var expires = "expires="+d.toGMTString();
          document.cookie = cname + "=" + cvalue + "; " + expires;
        }

        function window_height() {
           if (document.body) {
             winH = document.body.offsetHeight;
           }

          if (document.compatMode=='CSS1Compat' &&
             document.documentElement &&
             document.documentElement.offsetHeight ) {
             winH = document.documentElement.offsetHeight;
             return winH
          }

         if (window.innerHeight && window.innerHeight) {
            winH = window.innerHeight;
            return winH;
         }
      }     

      function window_width() {
        if (document.body) {
          winW = document.body.offsetWidth;
        }

       if (document.compatMode=='CSS1Compat' &&
          document.documentElement &&
          document.documentElement.offsetWidth ) {
          winW = document.documentElement.offsetWidth;
          return winW
       }

       if (window.innerWidth && window.innerWidth) {
         winW = window.innerWidth;
         return winW;
       }
     }      
       /* Upon page load, get the page width and height, and store in a JSON object/Cookie */
       setTimeout(function(){
         setCookie('w_w',JSON.stringify({'width':window_width(),'height':window_height()}))
       })

     </script>
    </head>
    <body>
      <?
        /* .........your PHP code...........*/
        /* .........your PHP code...........*/
        /* Access precise window dimensions */
        $xy=json_decode($_COOKIE['w_w']);
        $width=$xy->width;
        $height=$xy->height;
      ?>
     </body>
   </html>