function getPage(stranka, kam) {
  var httpRequest;
  if(typeof window.ActiveXObject !='undefined') {
    httpRequest =new ActiveXObject("Microsoft.XMLHTTP");
  }else{
    httpRequest =new XMLHttpRequest();
  }
  httpRequest.open("GET", stranka, true);
  httpRequest.onreadystatechange=function () {
    processRequest(httpRequest, kam);
  }
  httpRequest.send(null);
}

function processRequest(httpRequest, kam) {
  if (httpRequest.readyState ==4){
    if (( httpRequest.status >=200 && httpRequest.status < 300 ) || httpRequest.status ==304){
      if (typeof kam =='string'){
        document.getElementById(kam).innerHTML =httpRequest.responseText;
      }
      if (typeof kam =='function') {
        kam(httpRequest.responseText);
      }
    }else{
      document.getElementById(kam).innerHTML ='Chyba!';
    }
  }else{
    if (typeof kam =='string' && kam !='') {
      document.getElementById(kam).innerHTML =document.getElementById(kam).innerHTML ;
    }
  }
}

function ChangeVideo(video_id)
{
  getPage('video/video_tydne.php?vid='+video_id, 'video_tydne');
}