www.webreference.com/programming/javascript/w_b/index.html


  function ReplaceElementID(url,id)
  {
          var httpRequest;
          if (window.XMLHttpRequest)
          {
                  try { httpRequest = new XMLHttpRequest(); }
                  catch(e) {}
          }
          else if (window.ActiveXObject)
          {
                  try { httpRequest = new ActiveXObject("Msxml2.XMLHTTP"); }
                  catch(e)
                  {
                          try { httpRequest = new ActiveXObject("Microsoft.XMLHTTP"); }
                          catch(e) {}
                  }
          }
          if(! httpRequest)
          {
                  alert('\n\nGiving up :(\n\nCannot create an AJAX connection.');
                  return false;
          }
          httpRequest.onreadystatechange = function() { ContainerContents(httpRequest,id); };
          httpRequest.open('GET',url,true);
          httpRequest.send('');
  } // function makeRequestGET()