title: javascript mootools smooth scroll by 'x' amount of pixels
body: <p>I am trying to smooth scroll down 180px using javascript/mootools.</p>
  
  <p>I have the following js code:</p>
  
  <pre><code>document.documentElement.scrollTop = document.documentElement.scrollTop + 180;
  </code></pre>
  
  <p>But how can I for instance make this work over a course of 500ms so it animates the scroll rather than it jumping down (which it does at present).</p>
  
  <p>Cheers,
  Adi</p>