var http_request = getHttpRequest();
function getHttpRequest() {
        var http_request = false;

        if (window.XMLHttpRequest) { // Mozilla, Safari, ...
            http_request = new XMLHttpRequest();
            if (http_request.overrideMimeType) {
                // set type accordingly to anticipated content type
            //http_request.overrideMimeType('text/xml');
              http_request.overrideMimeType('text/html');
            }
        } 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;
        }
        return http_request;
}

function callServer(brand, model, divname) {
      var postData;
      postData = ( model == '') ? "brand=" + encodeURI(brand) : 
            "brand=" + encodeURI(brand) + "&model=" + encodeURI(model);

      http_request.open("POST", "handsetlistV3.inc.php", true);
      http_request.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
      http_request.setRequestHeader("Content-length", postData.length);
  //    http_request.setRequestHeader("Connection", "close");
      http_request.send(postData);
      http_request.onreadystatechange = function() {
        if (http_request.readyState == 4) {
          if (http_request.status == 200) {
//alert('updating ..');
            UpdateDiv(divname);
          } else {
            alert(http_request.responseText);
          }
        }
      };
      return false;
    }

function UpdateDiv(divname) {
  
  if(http_request.responseText == 'reload') {
    window.location.reload();
    return;
  }
  var mObj = document.getElementById(divname);
  mObj.innerHTML = http_request.responseText;
}

function updateHSmodel() {
  var bObj = document.getElementById('SelectBrand');
  callServer(bObj.value, '', 'SelectModelDiv');
}

function SelectHSmodel() {
  var bObj = document.getElementById('SelectBrand');
  var mObj = document.getElementById('SelectModel');

	if (bObj.value == 0 || mObj.value == 0)
		return false;

  callServer(bObj.value, mObj.value);
	return true;
}

function loadChoosePanel(brand, model) {
  var hsdiv = document.getElementById('handsetdiv');
  hsdiv.innerHTML = '<i>Loading handset selection box ...</i>';
  callServer('', '', 'handsetdiv');
}

function resetChoosePanel() {
  callServer('reset', '', 'handsetdiv');
}