agila-learning-examples/en/expanded-8-2/lesson-1/lesson.html

<!doctype html><html lang="en"><meta charset="utf-8"><title>Validate input and label controls</title><h1>Validate input and label controls</h1><p>15-minute session: read for 3 minutes, trace for 3, experiment for 7, and complete the check for 2. Spend longer whenever you need.</p><p>A visible label explains an input. The for attribute connects it to an id. Test empty input, 0, 1, 60, 61, and 1.5. HTML constraints help users but a real server must validate again because browser requests can be changed. This preview does not submit data to a server.</p><pre><code class="language-web">&lt;!doctype html&gt;
&lt;html lang=&quot;en&quot;&gt;&lt;meta charset=&quot;utf-8&quot;&gt;&lt;meta name=&quot;viewport&quot; content=&quot;width=device-width,initial-scale=1&quot;&gt;
&lt;title&gt;Agila study&lt;/title&gt;
&lt;main&gt;&lt;h1&gt;Study time&lt;/h1&gt;&lt;label for=&quot;minutes&quot;&gt;Minutes (1–60)&lt;/label&gt;&lt;input id=&quot;minutes&quot; type=&quot;number&quot; min=&quot;1&quot; max=&quot;60&quot;&gt;&lt;button id=&quot;check&quot;&gt;Check&lt;/button&gt;&lt;p id=&quot;result&quot; role=&quot;status&quot;&gt;&lt;/p&gt;&lt;/main&gt;
&lt;script&gt;document.getElementById(&quot;check&quot;).onclick=()=&gt;{const raw=document.getElementById(&quot;minutes&quot;).value;const n=Number(raw);document.getElementById(&quot;result&quot;).textContent=raw.trim()!==&quot;&quot;&amp;&amp;Number.isInteger(n)&amp;&amp;n&gt;=1&amp;&amp;n&lt;=60?&quot;Ready&quot;:&quot;Use a whole number from 1 to 60&quot;;};&lt;/script&gt;&lt;/html&gt;</code></pre><h3>Practice and evidence</h3><p>Keep three notes: your prediction, the actual result, and why they match or differ. The completion check grades understanding; the practice task builds skill.</p></html>