function colocar(objId,refId,x,y){
  ref_pos = Element.positionedOffset($(refId))
  obj = $(objId);
  x = ref_pos[0]-x;
  y = ref_pos[1]-y;
  Element.absolutize(obj);
  obj.setStyle({left:x+"px",top:y+"px"});
  Element.relativize(obj);
}

function mostrar(objId){
  $(objId).setStyle({visibility:'visible'});
}

function resizer(){
  if($('wrapper').getWidth()<$('main').getWidth()){
    $('wrapper').setStyle({width:$('main').getWidth()+"px"});
    $('footer').setStyle({width:$('main').getWidth()+"px"});
  };
}