// Get the HTTP Object
function getHTTPObject()
{
 if (window.ActiveXObject) 
  return new ActiveXObject("Microsoft.XMLHTTP");
 else if (window.XMLHttpRequest) 
  return new XMLHttpRequest();
 else {
  alert("Your browser does not support AJAX.");
  return null;
 }
}

// Change the value of the div
function setOutputModel()
{
 if(httpObject.readyState == 4)
 {
  document.getElementById('model').innerHTML = httpObject.responseText;
  document.getElementById('series').innerHTML = "Series : <select readonly></select";
 }
}

// Change the value of the div
function setOutputSeries()
{
 if(httpObject.readyState == 4)
 {
  document.getElementById('series').innerHTML = httpObject.responseText;
 }
}

function setOutputBattery()
{
 if(httpObject.readyState == 4)
 {
  document.getElementById('submit').innerHTML = httpObject.responseText;
 }
}	

// Implement business logic
function searchForModels()
{
 httpObject = getHTTPObject();

 if (httpObject != null) 
 {
  var mySelect = document.getElementById('manufacturer');
  var theIndx = mySelect.selectedIndex;
  httpObject.open("GET", 'search.php?type=model&term=' + mySelect.options[theIndx].value, true);
  httpObject.send(null);
  httpObject.onreadystatechange = setOutputModel;
 }
 else
  alert("No HTTP Object.");
}

function searchForSeries()
{
 httpObject = getHTTPObject();

 if (httpObject != null) 
 {
  var mySelect = document.getElementById('battery_model');
  var theIndx = mySelect.selectedIndex;
  httpObject.open("GET", 'search.php?type=series&term=' + mySelect.options[theIndx].value, true);
  httpObject.send(null);
  httpObject.onreadystatechange = setOutputSeries;
 }
 else
  alert("No HTTP Object.");
}

function searchForBatteries()
{ 
 httpObject = getHTTPObject();

 if (httpObject != null) 
 {
  var mySelect1 = document.getElementById('manufacturer');
  var theIndx = mySelect1.selectedIndex;
  var mySelect2 = document.getElementById('battery_model');
  var theIndx2 = mySelect2.selectedIndex;
  var mySelect3 = document.getElementById('battery_series');
  var theIndx3 = mySelect3.selectedIndex;
  httpObject.open("GET", 'search.php?type=battery&term=' + mySelect1.options[theIndx].value + ' ' + mySelect2.options[theIndx2].value + ' ' + mySelect3.options[theIndx3].value, true);
  httpObject.send(null);
  httpObject.onreadystatechange = setOutputBattery;
 }
 else
  alert("No HTTP Object.");
}

var httpObject = null;