// stores the reference to the XMLHttpRequest object
var xmlHttp = createXmlHttpRequestObject(); 

// 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;
    }
  }
  // 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 send_query()
{
  // proceed only if the xmlHttp object isn't busy
  if (document.getElementById("polldisp").innerHTML == '')
  {
	  if (xmlHttp.readyState == 4 || xmlHttp.readyState == 0)
	  {
	    // retrieve the name typed by the user on the form
	  //  name = encodeURIComponent(document.getElementById("myName").value);
	    // execute the quickstart.php page from the server
	    xmlHttp.open("GET", "send_poll.php" , true);  
	    // define the method to handle server responses
	    xmlHttp.onreadystatechange = ServerResponse_poll;
	    // make the server request
	    xmlHttp.send(null);
	  }
	  else if (document.getElementById("polldisp").innerHTML == '')
	  {
	    // if the connection is busy, try again after one second  
	    setTimeout('send_query()', 1000);
	  }
  }
  else
  {
  	document.getElementById("polldisp").innerHTML = '';
  }
  }

// executed automatically when a message is received from the server
function ServerResponse_poll() 
{
  // 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
      mes = xmlDocumentElement.firstChild.data;
      pos = 0; pos2 = 0;      
      str = '';
      
      while ((pos>=0) && (pos2>=0))
      {
   		 pos2 = mes.indexOf('  ',pos);
   		 str = str + mes.substr(pos,pos2-pos)+'<br/>';
   		 pos = pos2+1;
   		 //post = mes.indexOf(':');
//   		 post = mes.indexOf(':');
//	   	 pos2 = mes.indexOf(' ',pos+1);
      }
      
      // update the client display using the data received from the server
      document.getElementById("polldisp").innerHTML = 
                                            '<i>' + str + '</i>';
    } 
    // a HTTP status different than 200 signals an error
    else 
    {
      alert("There was a problem accessing the server: " + xmlHttp.statusText);
    }
  }
}