you&#39;re making a chat client which uses HTML and you don&#39;t
    want people inserting images into their messages, or style sheets, etc)
  - Added the tags &lt;address&gt;, &lt;var&gt;, &lt;cite&gt;, and &lt;def&gt;.
  - Added the &lt;hr&gt; tag.
  - Added two &quot;default images&quot; that are displayed when an &lt;img&gt; tag tries to show
    an image that couldn&#39;t be found, or was found but is a file type that isn&#39;t
    supported (e.g. &lt;img src=&quot;index.html&quot;&gt; would show an &