title: How to show Bootstrap modal using CSS which also blocks out rest of screen
body: <p>Excuse me but I am new to Bootstrap.</p>
  
  <p>I am wanting to show a modal using a CSS class rather than JavaScript (it is easier in this particular situation which uses ASP.NET UpdatePanels).</p>
  
  <p>I can do this simply with:</p>
  
  <pre><code>&lt;div id="popup" class="modal show"&gt;
  </code></pre>
  
  <p>But I want the rest of the screen to be blocked and greyed out, the same as when the JavaScript .modal("show") method is used.</p>
  
  <p>I tried adding <em>data-backdrop="static"</em> but that didn't do anything.</p>
  
  <p>Is there a way to do this?</p>