title: javascript element.scrollLeft not working
body: <p>I'm experimenting with sliders.</p>
  
  <p>I want to be able to scroll to a particular position of my slider and it seems from MDN docs that I could use element.scrollLeft to scroll to a particular position.</p>
  
  <p>I does not seem to be working for me though..
  <code>
  var container = document.getElementById('container');
  container.scrollLeft = 150;
  </code>
  <a href="http://codepen.io/veraz/pen/yVGWPP" rel="noreferrer">http://codepen.io/veraz/pen/yVGWPP</a></p>
  
  <p>window.scrollTo(150, 0) works though, but why?
  What's the difference between using one or the other?
  Thanks!</p>