title: Make div full width of screen, but show page scrollbar
body: <p>In my site, I have a topBar. I want this to be full screen, but I want the vertical page scrollbar to be shown, like the header for StackOverflow.</p>
  
  <p>My css is:</p>
  
  <pre><code>#topBar
  {
      background: black
      color: #fff;
      height: 60px;
      width:100%;
      padding:10px;
      top:0px;
      left:0px;
      position: fixed;
      z-index:1;
  }
  </code></pre>
  
  <p>How can I achieve this?</p>