Won't run using <script type="text/plain" class="language-markup">

[claide]

I tried using the basic prism highlighter using

<pre class="line-numbers language-markup">
	<code class="language-markup">
                 //some html here using &lt; and &gt;
        </code>
</pre>

and it works, but when using the script tag like

<script type="text/plain" class="language-markup">
        //some html here without using  &lt; and &gt;
</script>

it doesn't work as expected. Can you put an example how to achieve that? Thanks!