title: $sanitize Custom Whitelist
body: <p>The <code>$sanitize</code> service <a href="http://docs.angularjs.org/api/ngSanitize.$sanitize" rel="noreferrer">tells me that</a></p>
  
  <blockquote>
    <p>All safe tokens (from a whitelist) are then serialized back to
    properly escaped html string.</p>
  </blockquote>
  
  <p>I want to only display an even smaller subset of HTML (viz <code>em</code>,<code>p</code>,<code>a</code>, and <code>strong</code>). Is there a way to easily modify the <code>$service</code> whitelist without having to modify the core JavaScript?</p>