function getObj(name) {
  if (document.getElementById)
  {
  	this.obj = document.getElementById(name);
	this.style = document.getElementById(name).style;
  }
  else if (document.all)
  {
	this.obj = document.all[name];
	this.style = document.all[name].style;
  }
  else if (document.layers)
  {
   	this.obj = document.layers[name];
   	this.style = document.layers[name];
  }
}

function revifa() {
   var peu=new getObj('abaix');
   var alcada=document.body.clientHeight;
   var amplada=document.body.clientWidth;
   alcada+=30;
   amplada=0;/*Math.round(amplada/2)-430;*/

   peu.style.top=alcada+"px";
   peu.style.left=amplada+"px";
}