window.onload = function(){
//select the first button
var button1 = $('button1');

//select the first content element
var content1 = $('ultimos-comentarios');

//The height transition we attach to 'contentElement1'
var b1Toggle = new Fx.Style('ultimos-comentarios', 'height',{duration: 500});

//add an onclick event listener to button1
button1.addEvent('click', function(){
  //toggle height transition (hide-show)
  if(content1.getStyle('height').toInt() > 0){
    //hide
  b1Toggle.start(0);
  }else{
    //show
    b1Toggle.start(c1Height);
  }
  button1.toggleClass('button1_');
  return false;
});

//set css display:block for the contentElements
content1.setStyle('display','block');

//get the scrollSize of the contentElements
var c1Height = content1.getSize().scrollSize.y;
};