// <![CDATA[
Position.includeScrollOffsets = true;
  new Draggable('object1',{
    snap: function(x,y,draggable) {
      function constrain(n, lower, upper) {
        if (n > upper) return upper;
        else if (n < lower) return lower;
        else return n;
      }
     
      element_dimensions = Element.getDimensions(draggable.element);
      parent_dimensions = Element.getDimensions(draggable.element.parentNode);
      return[
        constrain(x, 0, parent_dimensions.width - element_dimensions.width),
        constrain(y, 0, parent_dimensions.height - element_dimensions.height)];
    },
    revert:false
  });
  
  new Draggable('object2',{
    snap: function(x,y,draggable) {
      function constrain(n, lower, upper) {
        if (n > upper) return upper;
        else if (n < lower) return lower;
        else return n;
      }
     
      element_dimensions = Element.getDimensions(draggable.element);
      parent_dimensions = Element.getDimensions(draggable.element.parentNode);
      return[
        constrain(x, 0, parent_dimensions.width - element_dimensions.width),
        constrain(y, 0, parent_dimensions.height - element_dimensions.height)];
    },
    revert:false
  });
// ]]>