;
</code></pre>

<pre><code class="language-html good">&lt;!-- Recommended --&gt;
&lt;img src="spreadsheet.png" alt="Spreadsheet screenshot."&gt;
</code></pre>

<h4 id="Separation_of_Concerns" class="numbered">Separation of Concerns</h4>

<p>Separate structure from presentation from behavior.</p>

<p>Strictly keep structure (markup), presentation (styling), and behavior
(scripting) apart, and try to keep the interaction between the three to an
absolute minimum.</p>

<p>That is, make sure documents and templ