change div width with prototypejs

HTML

<div id=test>

  <div class="bar" id="barId">
   blabla
  </div>

  <div class="bar">
   blabla
  </div>

</div>

CSS

.bar{
  background-color:green;
}

JavaScript

$("test").select('.bar').each(function(name, index) {
        name.setStyle({ width: '40px'});
});