function getScrollingPosition(){
  //array for X and Y scroll position
  var position = [0, 0];

  //if the window.pageYOffset property is supported
  if (typeof window.pageYOffset != 'undefined')
  {
    //store position values
    position = [
        window.pageXOffset,
        window.pageYOffset
    ];
  }

  //if the documentElement.scrollTop property is supported
  //and the value is greater than zero
  if (typeof document.documentElement.scrollTop != 'undefined'
      && document.documentElement.scrollTop > 0)
  {
    //store position values
    position = [
        document.documentElement.scrollLeft,
        document.documentElement.scrollTop
    ];
  }

  //if the body.scrollTop property is supported
  else if(typeof document.body.scrollTop != 'undefined')
  {
    //store position values
    position = [
        document.body.scrollLeft,
        document.body.scrollTop
    ];
  }

  //return the array
  return position;
}

function getViewportSize(){
  var size = [0,0];

  if (typeof window.innerWidth != 'undefined')
  {
    size = [
        window.innerWidth,
        window.innerHeight
    ];
  }
  else if (typeof document.documentElement != 'undefined'
      && typeof document.documentElement.clientWidth != 'undefined'
      && document.documentElement.clientWidth != 0)
  {
    size = [
        document.documentElement.clientWidth,
        document.documentElement.clientHeight
    ];
  }
  else
  {
    size = [
        document.getElementsByTagName('body')[0].clientWidth,
        document.getElementsByTagName('body')[0].clientHeight
    ];
  }

  return size;
}

function getPageDimensions(){
  var body = document.getElementsByTagName("body")[0];
  var bodyOffsetWidth = 0;
  var bodyOffsetHeight = 0;
  var bodyScrollWidth = 0;
  var bodyScrollHeight = 0;
  var pageDimensions = [0, 0];

  if (typeof document.documentElement != "undefined" && typeof document.documentElement.scrollWidth != "undefined"){
    pageDimensions[0] = document.documentElement.scrollWidth;
    pageDimensions[1] = document.documentElement.scrollHeight;
  }

  bodyOffsetWidth = body.offsetWidth;
  bodyOffsetHeight = body.offsetHeight;
  bodyScrollWidth = body.scrollWidth;
  bodyScrollHeight = body.scrollHeight;

  if (bodyOffsetWidth > pageDimensions[0])
  {
    pageDimensions[0] = bodyOffsetWidth;
  }

  if (bodyOffsetHeight > pageDimensions[1])
  {
    pageDimensions[1] = bodyOffsetHeight;
  }

  if (bodyScrollWidth > pageDimensions[0])
  {
    pageDimensions[0] = bodyScrollWidth;
  }

  if (bodyScrollHeight > pageDimensions[1])
  {
    pageDimensions[1] = bodyScrollHeight;
  }

  return pageDimensions;
}

function close_page_transition(dialog){
  var dropSheet = document.getElementById("dropSheet");
  var dialog = document.getElementById("dialog");

  dropSheet.parentNode.removeChild(dropSheet);
  dialog.parentNode.removeChild(dialog);

  return true;
}

function display_page_transition(){
  var body = document.getElementsByTagName("body")[0];
  var pageDimensions = getPageDimensions();
  var viewportSize = getViewportSize();

  if (viewportSize[1] > pageDimensions[1]) pageDimensions[1] = viewportSize[1];

  var dropSheet = document.createElement("div");

  dropSheet.setAttribute("id", "dropSheet");
  dropSheet.style.position = "absolute";
  dropSheet.style.left = "0";
  dropSheet.style.top = "0";
  dropSheet.style.width = pageDimensions[0] + "px";
  dropSheet.style.height = pageDimensions[1] + "px";
  body.appendChild(dropSheet);

  try {
    var dialog = document.createElement("img");
	  dialog.setAttribute("id", "dialog");
    dialog.style.visibility = "hidden";
    dialog.style.position = "absolute";
		dialog.src = "images/sites/ajax_processing.gif";
		dialog.height = 128;
		dialog.width = 128;

		body.appendChild(dialog);

    var scrollingPosition = getScrollingPosition();

    dialog.style.left = scrollingPosition[0] + parseInt(viewportSize[0] / 2) - parseInt(dialog.offsetWidth / 2) + "px";
    dialog.style.top = scrollingPosition[1] + parseInt(viewportSize[1] / 2) - parseInt(dialog.offsetHeight / 2) + "px";
    dialog.style.visibility = "visible";

	} catch(error){
		
    dropSheet.parentNode.removeChild(dropSheet);
    return true;
  }

	return false;
}