Position.getPageSize = function() {
  var xScroll, yScroll;

  if (window.scrollMaxX) {  
    xScroll = window.innerWidth  + window.scrollMaxX;
    yScroll = window.innerHeight + window.scrollMaxY;
  } else {
    xScroll = document.body.scrollWidth;
    yScroll = document.body.scrollHeight;
  } 
  
  var windowWidth, windowHeight;
  if (self.innerHeight) { // all except Explorer
    windowWidth = self.innerWidth;
    windowHeight = self.innerHeight;
  } else if (document.documentElement && document.documentElement.clientHeight) { // Explorer 6 Strict Mode
    windowWidth = document.documentElement.clientWidth;
    windowHeight = document.documentElement.clientHeight;
  } else if (document.body) { // other Explorers
    windowWidth = document.body.clientWidth;
    windowHeight = document.body.clientHeight;
  }
  // for small pages with total height less then height of the viewport
  pageHeight = Math.max(windowHeight, yScroll);

  // for small pages with total width less then width of the viewport
  pageWidth = Math.max(windowWidth, xScroll);

  return { page: { width: pageWidth, height: pageHeight }, window: { width: windowWidth, height: windowHeight } };
}