title: How to display image in the center of a div
body: <p>I have div with ajax-loader gif image</p>
  
  <pre class="lang-html prettyprint-override"><code>&lt;div id="mydiv" style="height: 400px; text-align: center;"&gt;
      &lt;img src="/Content/ajax-loader.gif" class="ajax-loader"/&gt;
  &lt;/div&gt;
  </code></pre>
  
  <pre class="lang-css prettyprint-override"><code>.ajax-loader
  {
      /*hidden from IE 5-6 */
      margin-top: 0; /* to clean up, just in case IE later supports valign! */
      vertical-align: middle;
      margin-top: expression(( 150 - this.height ) / 2); 
  }
  </code></pre>
  
  <p>But could not get it displayed in the center (both vertically and horizontally). Need help with that.</p>