title: background-image doesn't appear if <div> is empty?
body: <p>I created a <code>&lt;div&gt;</code> first thing in the <code>&lt;body&gt;</code> to draw a top line at the top of the page:</p>
  
  <pre><code>&lt;body&gt;
      &lt;div class="bordertop"&gt;&lt;/div&gt;
      .....
  &lt;/body&gt;
  </code></pre>
  
  <p>and the style:</p>
  
  <pre><code>body {
      font-family: Helvetica, Arial, sans-serif;
      -webkit-text-size-adjust: 100%;
      margin:0;
  }
  .bordertop {
      background-image: url(../images/top_border.png);
      background-repeat: repeat-x;    
  }
  </code></pre>
  
  <p>However, the <code>top_border image</code> doesn't appear unless I write some text inside the <code>&lt;div&gt;</code> but I don't want to. How could I fix this?</p>