var req;
var reqTimeout;
function loadDoc(params, tag) {
  req = null;
  if (window.XMLHttpRequest) {
    try { req = new XMLHttpRequest(); } catch (e){}
  }
  else if (window.ActiveXObject) {
    try { req = new ActiveXObject('Msxml2.XMLHTTP'); } catch (e){
      try { req = new ActiveXObject('Microsoft.XMLHTTP'); } catch (e){}
    }
  }
  if (req) {
    req.onreadystatechange = function () {
      if (req.readyState == 4) {
        clearTimeout(reqTimeout);
        if (req.status == 200) { document.getElementById(tag).innerHTML=req.responseText; }
        else { alert("Не удалось получить данные:\n" + req.statusText); }
      }
    }
    req.open("GET", "ajax.pl?"+tag+"="+params+'&'+Math.random());
    req.send(null);
    reqTimeout = setTimeout("req.abort();", 5000);
  } else { alert("Браузер не поддерживает AJAX"); }
}