js remove certain words that don't match
<p>I have a js string...</p>

<pre><code>var string = "Hi how are you &lt;b&gt;today&lt;/b&gt;";
</code></pre>

<p>I now have a new js string... </p>

<pre><code>var newstring = "are today";
</code></pre>

<p>I want to remove all the words from <code>var string</code> that don't match <code>var newstring</code>. I would also like to keep the tags that are associated with those words, if any.</p>

<pre><code>Example Result:
are &lt;b&gt;today&lt;/b&gt; 
</code></pre>
