title: Does prototype setAttribute works with element class selector
body: <p>I am using prototype to change the onclick function of the button. The following code is working well.</p>
  
  <pre><code>$('button_id').setAttribute('onclick','test();');
  </code></pre>
  
  <p>but the following is not working </p>
  
  <pre><code>$$('div#divid button.buttonclass').setAttribute('onclick','test();'); or
  
  $$('button.buttonclass').setAttribute('onclick','test();');
  </code></pre>
  
  <p>I just want to change the button <code>onclick</code> function. The button is inside a div element. Button has the class name <code>button</code> only and do not have the id attribute.</p>