Find all HTML tags used on a webpage : <p>I need a list of all HTML-tags used on a specific page.</p>

<p>My goal is to get a list like this</p>

<pre><code>&lt;a&gt;
&lt;p&gt;
&lt;em&gt;
&lt;body&gt;
</code></pre>

<p>and so on. I will then paste it into a text editor and remove duplicates and finally process the result in a Javascript.</p>

<p>How can I achieve this?</p>
