function ChangePage(p, n) {
      try {
        if($("pi_"+p)) {
          $("pi_"+now_page).style.display="none";
          now_page=p; 
          $("pi_"+p).style.display="block";
          return;
        }
      } catch (e) { }
      
      makeRequest();
      
      $("loading").style.display="block";
      
      http_request.onreadystatechange = function() {
        if (http_request.readyState == 4) {
          if (http_request.status == 200) {
            var retCode = http_request.responseText;
            
            var pDiv=document.createElement("div");
            pDiv.id="pi_"+p;
            pDiv.innerHTML = retCode;
               
            $("pi_"+now_page).style.display="none";
            $("mediabody").appendChild(pDiv);
            now_page=p; 
            $("loading").style.display="none";
          }
        }
      }

      to='/media_playlist_listcontent.php?pID='+now_pid+'&numrw='+n+'&page='+p;
      http_request.open('GET', to, true);
      http_request.send(null);
    }