My XHR and JSON

xhrjson.js

PKUTIL.loadQueue = Array();
PKUTIL.XHRinProgress = false;
PKUTIL.XHRTimer = -1;

PKUTIL.load = function(theFileName, aSync, completion)
{
  if (device.platform != "WinCE")
  {
    PKUTIL._load(theFileName, aSync, completion);
    return;
  }
  console.log("Pushing request to load XHR: " + theFileName);
  PKUTIL.loadQueue.push(function()
  {
    console.log("Processing XHR " + theFileName);
    PKUTIL._load(theFileName, aSync, completion);
  });

  if (PKUTIL.XHRTimer < 0)
  {
    PKUTIL.XHRTimer = setInterval(PKUTIL._XHRQueue, 100);
  }
}

PKUTIL._XHRQueue = function()
{
  if (PKUTIL.XHRinProgress)
  {
    return;
  }
  if (PKUTIL.loadQueue.length > 0)
  {
    var f = PKUTIL.loadQueue.pop();
    f();
  }
}

PKUTIL._load = function(theFileName, aSync, completion)
{
  if (!window.XMLHttpRequest)
  {
    if (completion)
    {
      completion(PKUTIL.COMPLETION_FAILURE, "This browser does not support XMLHttpRequest.");
      return;
    }
  }

  PKUTIL.XHRinProgress = true;

  var r = new XMLHttpRequest();
  r.onreadystatechange = function()
  {
    if (r.readyState == 4)// loaded
    {
      if (r.status == 200 || r.status == 0)// success
      {
        if (completion)
        {
          console.log("success loading " + theFileName + ", length " + r.responseText.length);
          completion(PKUTIL.COMPLETION_SUCCESS, r.responseText);
          PKUTIL.XHRinProgress = false;
        }
      } else// failed to load
      {
        if (completion)
        {
          completion(PKUTIL.COMPLETION_FAILURE, r.status);
          PKUTIL.XHRinProgress = false;
        }
      }
    }
  }
  if (device.platform == "WinCE" && theFileName.substr(0, 4) != "http")
  {
    r.open('GET', "/app/www/" + theFileName, true);
  } else
  {
    r.open('GET', theFileName, aSync);
  }
  r.send();

}

    
/**
 *
 * Retrieves a JSON string from the specified URL, and executes completion.
 * Completion must be of the form ( success, data ).
 *
 * @param theURL     the URL or Filename
 * @param completion function of the from ( success, data )
 *
 */
PKUTIL.loadJSON = function(theURL, completion)
{
  PKUTIL.load(theURL, true, function(success, data)
  {
    var theParsedData =
    {
    };

    if (success)
    {
      try
      {
        theParsedData = JSON.parse(data);
      } catch (err)
      {
        console.log("Failed to parse JSON from " + theURL);
        success = COMPLETION_FAILURE;
      }
    }
    // call completion, if available
    if (completion)
    {
      completion(success, theParsedData);
    }
  });
}