function gen_price()
{
var xmlHttp;
try { xmlHttp=new XMLHttpRequest(); }
catch (e) {
  try
    {
    xmlHttp=new ActiveXObject("Msxml2.XMLHTTP");
    }
  catch (e)
    {
    try
      {
      xmlHttp=new ActiveXObject("Microsoft.XMLHTTP");
      }
    catch (e)
      {
      alert("Your browser does not support AJAX!");
      return false;
      }
    }
  }
  xmlHttp.onreadystatechange=function()
    {
    if(xmlHttp.readyState==4)
      {
      document.getElementById('ajaxprice').innerHTML=xmlHttp.responseText;
      }
    }
  xmlHttp.open("GET","/ajax/gen_price.php?prod="+document.detail.kod.value+"&parameter="+document.detail.velkost.value,true);
  xmlHttp.send(null);
  }