var foo = null; // object

function doMove() {
  var contea;
  contea=parseInt(foo.style.top);
  
  if(contea<100){
  foo.style.top = parseInt(foo.style.top)+3+'px';
  setTimeout(doMove,5); // call doMove in 20msec
  }else{
	doMoveArriba();
  }
  contea=contea+1;
}

function doMoveArriba() {
  var contearri;
  contearri=parseInt(foo.style.top);
  
  if(contearri>1){
  foo.style.top = parseInt(foo.style.top)-1+'px';
  setTimeout(doMoveArriba,2); // call doMove in 20msec
  }else{
  foo.style.position ="absolute";
  }
  contearri=contearri+1;
}

function init() {
	var prianch;
	prianch=screen.width;
  	foo = document.getElementById('fooObject'); // get the "foo" object
  	foo.style.top = '-120px'; // set its initial position to 0px
	
	if(prianch<='800'){
		foo.style.left='500px';
	}else if(prianch<='1024'){
		foo.style.left='590px';
	}else if(prianch<='1280'){
		foo.style.left='700px';
	}else if(prianch>'1280'){
		foo.style.left='800px';
	}
	
		
  	doMove(); // start animating
}