// stores the reference to the XMLHttpRequest object
var xmlHttp = createXmlHttpRequestObject();
// holds the remote server address
var surveyServerAddress = "survey";
//var serverAddress;
var serverAddressToSend;
// retrieves the XMLHttpRequest object
function createXmlHttpRequestObject()
{
  // will store the reference to the XMLHttpRequest object
  var xmlHttp;
  // if running Internet Explorer
  if(window.ActiveXObject)
  {
    try
    {
      xmlHttp = new ActiveXObject("Microsoft.XMLHTTP");
    }
    catch (e)
    {
      xmlHttp = false;
    }
  }
  // if running Mozilla or other browsers
  else
  {
    try
    {
      xmlHttp = new XMLHttpRequest();
    }
    catch (e)
    {
      xmlHttp = false;
    }
  }
  //**************************
  if(window.ActiveXObject)
  {
    try
    {
      xmlHttp = new ActiveXObject("Microsoft.XMLHTTP");
    }
    catch (e)
    {
      xmlHttp = false;
    }
  }
  // if running Mozilla or other browsers
  else
  {
    try
    {
      xmlHttp = new XMLHttpRequest();
    }
    catch (e)
    {
      xmlHttp = false;
    }
  }
  // return the created object or display an error message
  if (!xmlHttp)

    alert("Error creating the XMLHttpRequest object.");
  else
    return xmlHttp;
}

// make asynchronous HTTP request using the XMLHttpRequest object
function survey(form, answer, server)
{
	var error = 0;
	var flag = false;
	var valueArray = new Array();
	var answerValue;
	var k=0;
	var id;


	//serverAddress = server;
	//alert (serverAddress);
  for(i=0; i < document.forms[form].elements.length; i++)
  {
  	name = document.forms[form].elements[i].name;
  	len = (document.forms[form])[name].length;
  	flag = false;
  	answerValue = "";
  	for(j=0; j < len; j++) {
  		id = (((document.forms[form])[name])[j].id);
  		if (((document.forms[form])[name])[j].checked){
  		  flag = true;
  		  answerValue = ((document.forms[form])[name])[j].value;
  		  answerValue = escape(answerValue);
  		}
  	}
  	if (answerValue)
  	  valueArray[k] = id + "_" + answerValue;
  	else
  		valueArray[k] = "Null";
  	if (!flag)
  	  error++;
  	i = i + len - 1;
  	k++;

  }
  if (error) {
  	alert (answer);
    return false;
  }
  else {
  	for(i=0; i < k; i++) {
  	  if (i == 0)
  	    serverAddressToSend = surveyServerAddress + "?" + valueArray[i];
  	  else
  	    serverAddressToSend = serverAddressToSend + "&" + valueArray[i];
  	}
  	validateSurvey();
  	//return true;
  }
}


function validateSurvey()
{
      //alert ('Gracias ' + serverAddressToSend);
      // proceed only if the xmlHttp object isn't busy
      if (xmlHttp.readyState == 4 || xmlHttp.readyState == 0)
      {
        // execute the quickstart.php page from the server
        xmlHttp.open("GET", serverAddressToSend, true);
        // define the method to handle server responses
        xmlHttp.onreadystatechange = handleServerResponseSurvey;
        // make the server request
        xmlHttp.send(null);
      }
      else
        // if the connection is busy, try again after one second
        setTimeout('validateSurvey()', 1000);
}

// executed automatically when a message is received from the server
function handleServerResponseSurvey()
{
	var qty;
	var field;
  // move forward only if the transaction has completed
  if (xmlHttp.readyState == 4)
  {
    // status of 200 indicates the transaction completed successfully
    if (xmlHttp.status == 200)
    {
      // extract the XML retrieved from the server
      xmlResponse = xmlHttp.responseXML;
      // obtain the document element (the root element) of the XML structure
      xmlDocumentElement = xmlResponse.documentElement;
      // get the text message, which is in the first child of
      // the the document element
      error = xmlDocumentElement.getElementsByTagName("error")[0].firstChild.data;
      if (error == 0) {
      	document.getElementById("surveyQuestions").style.display = 'none';
      	document.getElementById("surveyResults").style.display = '';
      	totalQuestions = xmlDocumentElement.getElementsByTagName("totalQuestions")[0].firstChild.data;
      	for(i=0; i < totalQuestions; i++)
        {
        	totalAnswers = xmlDocumentElement.getElementsByTagName("totalAnswers"+i)[0].firstChild.data;
        	for(j=0; j < totalAnswers; j++)
          {
          	answer = xmlDocumentElement.getElementsByTagName("answer"+i+j)[0].firstChild.data;
          	document.getElementById('answer'+i+j).innerHTML = answer;
          }
        }
      }
      else {
      	document.getElementById("surveyQuestions").style.display = '';
      	document.getElementById("surveyResults").style.display = 'none';
      }
    }
    // a HTTP status different than 200 signals an error
    else
    {
      alert("There was a problem accessing the server: " + xmlHttp.statusText);
    }
  }
}