function makeRequest(container, url) {

    var http_request = false;
    if (window.XMLHttpRequest) { // Mozilla, Safari,...
      http_request = new XMLHttpRequest();
    } else if (window.ActiveXObject) { // IE
      try {
        http_request = new ActiveXObject("Msxml2.XMLHTTP");
      } catch (e) {
        try {
          http_request = new ActiveXObject("Microsoft.XMLHTTP");
        } catch (e) {}
      }
    }

    if (!http_request) {
      alert('Giving up :( Cannot create an XMLHTTP instance');
      return false;
    }

    // ????????? alterContents()
    http_request.onreadystatechange = function() { 
              displayContents(document.getElementById(container),http_request); 
    }
    http_request.open('GET', url, true);
    http_request.send(null);

}
function displayContents(container, http_request) {
    if (http_request.readyState == 4) {
      container.innerHTML = http_request.responseText
    }
  }