numbered">HTML Validity</h4>

<p>Use valid HTML where possible.</p>

<p>Use valid HTML code unless that is not possible due to otherwise unattainable
performance goals regarding file size.</p>

<p> Use tools such as the
<a href="https://validator.w3.org/nu/">W3C HTML validator</a>
to test.</p>

<p>Using valid HTML is a measurable baseline quality attribute that contributes to
learning about technical requirements and constraints, and that ensures proper
HTML usage.</p>

<pre><code class="language-html bad">