/*  AJAX Functions
* ajax.js  Ver. 1.0
* 
* Copyright (c) 2005  University Corporation for Atmospheric Research(UCAR) 
* All Rights Reserved.
* Niles Oien from Frank Hage's April 2005 work.
* 
* This is the part that runs on the client, puts together the XML
* message from make_prod.php running on the server, and does all the right things.
*
*/


/*************************************************************************************/
var ns4up = (window.XMLHttpRequest) ? 1 : 0;  // browser sniffer
var ie4up = (window.ActiveXObject) ? 1 : 0;

var doc_height,doc_width;

if (ns4up)
{
  doc_width = window.innerWidth;
  doc_height = window.innerHeight;
}
else if (ie4up)
{
  doc_width = document.body.clientWidth;
  doc_height = document.body.clientHeight;
}


var req;
var xml;

/*************************************************************************************
 * Example taken From: Very Dynamic Web Interfaces by Drew McLellan, http://www.xml.com
 */
function processReqChange()
{
  // only if req shows "loaded"
  // alert("At critical point with : " + req.readyState + ", " + req.statusText); 
  if (req.readyState == 4)
  {
    // only if "OK"

/////////////////////////////////////////
//
// The following code traps an error that should not now occur.
// See comments in ciddView.php relating to the "oddball error".
//
    var st_test;
    try
    {
      st_test = req.status;
    }
    catch(e)
    {
      alert( "oddball error" );
      req.abort();
      return;
    }

///////////////////////////////////////////

    if (req.status == 200)
    {
      // ...processing statements go here...
      //resp =  req.responseText;

      xml = req.responseXML;
      prod = xml.getElementsByTagName("product");
      set_radar_http( prod[0] );

    }
    else
    {
      alert("There was a problem retrieving the XML data:\n" +
            req.statusText);
    }
  }
}

/************************************************************************************
 * set_http: Set an element's innerHTML and make it visible
 *
 * Tags: 	prod_html - Contains Html to be inserted
 * 			target		Div element for insertion of the html.
 *          status_html  Contains HTML to for Displaying Status.
 */ 

function set_http(elem)
{
  html = elem.getElementsByTagName("prod_html")[0].firstChild.data;
  target = elem.getElementsByTagName("target")[0].firstChild.data;
  _el(target).innerHTML = html;

  if(elem.getElementsByTagName("status_html")[0])
  {
    status_html = elem.getElementsByTagName("status_html")[0].firstChild.data;
    if(_el('status_panel')) _el('status_panel').innerHTML = status_html;
  }

  pop(_el(target));
    
}

/************************************************************************************
 * set_radar_http: Set an element's innerHTML and make it visible
 *
 * Tags: 	prod_html - Contains Html to be inserted
 *          status_html  Contains HTML to for Displaying Status.
 * 			target	Div element for insertion of the prrod_html.
 *          frame      - Ordered list of image names for anim
 */ 

function set_radar_http(elem)
{

  html = elem.getElementsByTagName("prod_html")[0].firstChild.data;
  target = elem.getElementsByTagName("target")[0].firstChild.data;
  message_html = elem.getElementsByTagName("message_html")[0].firstChild.data;

  _el(target).innerHTML = html;

  if (_el('message_panel')) _el('message_panel').innerHTML = message_html;

  //alert("Going to get frames...");
//
// NOTE - in order for this to work on IE, we need the
// next line to be :
//
// var frames = elem.getElementsByTagName("frame");
//
// Not :
//
//     frames = elem.getElementsByTagName("frame");
//
  var frames = elem.getElementsByTagName("frame");
  nframes =  frames.length;
  //alert("Got " + nframes + " frames.");

  for (var i = 0; i < frames.length; i++)
  {
    img_arr[i] = new Image();
    img_arr[i].src = frames[i].firstChild.data;
    // alert("Frame:" +  img_arr[i].src);
  }

  cur_frame = nframes -1;
    
}

/*************************************************************************************/
function loadXMLDoc(url)
{
  // branch for native XMLHttpRequest object
  if (window.XMLHttpRequest)
  {
    req = new XMLHttpRequest();
    req.onreadystatechange = processReqChange;
    req.open("GET", url, true);
    req.send(null);
  // branch for IE/Windows ActiveX version
  }
  else if (window.ActiveXObject)
  {
    req = new ActiveXObject("Microsoft.XMLHTTP");
    if (req)
    {
      req.onreadystatechange = processReqChange;
      req.open("GET", url, true);
      req.send();
    }
  }
}