BodyDisabler = {

  div: false,

  getPageSize: function() {

    var xScroll, yScroll;

    if (window.innerHeight && window.scrollMaxY) {
      xScroll = window.innerWidth + window.scrollMaxX;
      yScroll = window.innerHeight + window.scrollMaxY;
    } else if (document.body.scrollHeight > document.body.offsetHeight){ // all but Explorer Mac
      xScroll = document.body.scrollWidth;
      yScroll = document.body.scrollHeight;
    } else { // Explorer Mac...would also work in Explorer 6 Strict, Mozilla and Safari
      xScroll = document.body.offsetWidth;
      yScroll = document.body.offsetHeight;
    }

    var windowWidth, windowHeight;

    if (self.innerHeight) {	// all except Explorer
      if(document.documentElement.clientWidth){
        windowWidth = document.documentElement.clientWidth;
      } else {
        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
    if(yScroll < windowHeight){
      pageHeight = windowHeight;
    } else {
      pageHeight = yScroll;
    }

    // for small pages with total width less then width of the viewport
    if(xScroll < windowWidth){
      pageWidth = xScroll;
    } else {
      pageWidth = windowWidth;
    }

    return [pageWidth,pageHeight];
  },

  init: function(){
    d = Builder.node('div', {
      id: 'bodyDisabler'
    });
    document.body.appendChild(d);
    
  },

  start: function(){

    d = $('bodyDisabler');
    a = BodyDisabler.getPageSize();
    w = a[0]+'px';
    h = a[1]+'px';
    
    d.setStyle({
      position: 'absolute',
      top: '0px',
      left: '0px',
      width: w,
      height: h,
      backgroundColor: '#cccccc',
      opacity: '0.5'
    });
    
    d.show();
  },
  
  stop: function(){
    d = $('bodyDisabler');
    d.hide();
  }

}

Event.observe(window, 'load', function(){
  BodyDisabler.init()
});