GizDevCraft Editor - Focus Management & Trapping

HTML

CSS

<a class="skip-link" href="#lessonMain">Skip to practice area</a>
<main id="lessonMain" class="lesson-shell a11y-playground">
  <section class="demo-card" aria-labelledby="a11yTitle">
    <span class="eyebrow">Focus Management &amp; Trapping</span>
    <h1 id="a11yTitle">Accessibility practice area</h1>
    <p>Use Tab, Shift+Tab, Enter, Space, and Escape while you edit labels, focus, errors, contrast, ARIA states, and reduced motion.</p>

    <nav class="a11y-nav" aria-label="Accessibility practice sections">
      <a href="#a11yForm">Form</a>
      <a href="#a11yDialogSection">Dialog</a>
      <a href="#a11yImageSection">Images</a>
    </nav>

    <form id="a11yForm" class="a11y-panel" novalidate>
      <h2>Accessible signup form</h2>
      <div id="errorSummary" class="error-summary" role="alert" tabindex="-1" hidden></div>

      <label for="studentName">Name</label>
      <input id="studentName" name="studentName" autocomplete="name" aria-describedby="nameHint">
      <p id="nameHint" class="hint">Enter the name shown on your certificate.</p>

      <label for="studentEmail">Email</label>
      <input id="studentEmail" name="studentEmail" type="email" autocomplete="email" aria-describedby="emailHint emailError">
      <p id="emailHint" class="hint">Use an email address you check often.</p>
      <p id="emailError" class="field-error" hidden>Enter an email address with an @ symbol.</p>

      <fieldset>
        <legend>Preferred lesson format</legend>
        <label><input type="radio" name="format" value="text" checked> Text lesson</label>
        <label><input type="radio" name="format" value="video"> Video with captions</label>
      </fieldset>

      <button class="action" type="submit">Check form</button>
      <p id="formStatus" role="status"></p>
    </form>

    <section id="a11yDialogSection" class="a11y-panel" aria-labelledby="dialogSectionTitle">
      <h2 id="dialogSectionTitle">Focus and ARIA state</h2>
      <button id="menuButton" class="action" type="button" aria-expanded="false" aria-controls="practiceMenu">Toggle menu</button>
      <ul id="practiceMenu" class="practice-menu" hidden>
        <li><a href="#a11yForm">Review form labels</a></li>
        <li><a href="#a11yImageSection">Review image text</a></li>
      </ul>

      <button id="openDialog" class="action" type="button">Open focus dialog</button>
      <dialog id="lessonDialog" aria-labelledby="dialogTitle">
        <h3 id="dialogTitle">Focus practice</h3>
        <p>Focus moves here when the dialog opens and returns to the opener when it closes.</p>
        <button id="closeDialog" type="button">Close dialog</button>
      </dialog>
    </section>

    <section id="a11yImageSection" class="a11y-panel" aria-labelledby="imageSectionTitle">
      <h2 id="imageSectionTitle">Images and motion</h2>
      <figure>
        <div class="image-demo" role="img" aria-label="Dashboard card showing readable labels and clear focus states">Image preview</div>
        <figcaption>Informative images need useful text alternatives.</figcaption>
      </figure>
      <div class="motion-card">Motion should be calm when reduced motion is requested.</div>
    </section>

    <details class="code-reference">
      <summary>Lesson code reference</summary>
      <pre class="code-sample"><code>const dialog = document.querySelector(&#039;dialog&#039;);
const opener = document.querySelector(&#039;#open-dialog&#039;);

opener.addEventListener(&#039;click&#039;, () =&gt; {
  dialog.showModal();
  dialog.querySelector(&#039;button, [href], input&#039;)?.focus();
});

dialog.addEventListener(&#039;close&#039;, () =&gt; opener.focus());</code></pre>
    </details>
  </section>
</main>

body {
  margin: 0;
  min-height: 100vh;
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  background: #f8fafc;
  color: #111827;
}

.lesson-shell {
  min-height: 100vh;
  display: grid;
  place-items: center;
  padding: 2rem;
}

.demo-card {
  width: min(760px, 100%);
  background: #ffffff;
  border: 1px solid #dbe3ef;
  border-radius: 12px;
  padding: 2rem;
  box-shadow: 0 18px 45px rgb(15 23 42 / .10);
  text-align: center;
}

.eyebrow {
  display: inline-block;
  margin-bottom: .75rem;
  color: #4f46e5;
  font-weight: 800;
  font-size: .78rem;
  letter-spacing: .08em;
  text-transform: uppercase;
}

h1 {
  margin: 0 0 .75rem;
  font-size: clamp(1.8rem, 4vw, 3rem);
}

p {
  color: #536471;
  line-height: 1.7;
}

button {
  border: 0;
  border-radius: 8px;
  padding: .75rem 1rem;
  background: #4f46e5;
  color: white;
  font-weight: 800;
  cursor: pointer;
}

.demo-target {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1rem;
  margin-top: 1.5rem;
}

.box {
  border: 1px solid #dbe3ef;
  border-radius: 8px;
  padding: 1.25rem;
  background: #f8fafc;
  font-weight: 800;
}

.featured {
  background: #eef2ff;
  color: #3730a3;
}
.skip-link { position: fixed; inset-block-start: .75rem; inset-inline-start: .75rem; z-index: 10; transform: translateY(-160%); background: #111827; color: #ffffff; padding: .75rem 1rem; border-radius: 8px; }
.skip-link:focus { transform: translateY(0); }
.a11y-playground .demo-card { max-width: 980px; text-align: left; }
.a11y-nav { display: flex; flex-wrap: wrap; gap: .75rem; margin-block: 1rem; }
.a11y-panel { display: grid; gap: .75rem; border: 1px solid #d7dde8; border-radius: 8px; padding: 1rem; margin-block: 1rem; background: #ffffff; }
.a11y-panel label { font-weight: 700; }
.a11y-panel input { min-height: 2.5rem; border: 1px solid #64748b; border-radius: 8px; padding: .55rem .7rem; font: inherit; }
fieldset { display: grid; gap: .55rem; border: 1px solid #cbd5e1; border-radius: 8px; padding: 1rem; }
.action, .a11y-nav a, dialog button { border: 0; border-radius: 8px; background: #1d4ed8; color: #ffffff; padding: .7rem 1rem; font-weight: 800; text-decoration: none; width: fit-content; }
.action:focus-visible, .a11y-nav a:focus-visible, input:focus-visible, summary:focus-visible, dialog button:focus-visible { outline: 3px solid #f59e0b; outline-offset: 3px; }
.hint { color: #475569; margin: 0; }
.field-error, .error-summary { color: #7f1d1d; background: #fee2e2; border: 1px solid #991b1b; border-radius: 8px; padding: .75rem; }
.practice-menu { display: grid; gap: .5rem; padding: 1rem 1.25rem; background: #f8fafc; border-radius: 8px; }
dialog { max-width: 28rem; border: 1px solid #334155; border-radius: 8px; padding: 1.25rem; }
dialog::backdrop { background: rgb(15 23 42 / .55); }
.image-demo { display: grid; place-items: center; min-height: 8rem; border-radius: 8px; background: #dbeafe; color: #1e3a8a; font-weight: 800; }
.motion-card { border-radius: 8px; background: #ecfdf5; color: #14532d; padding: 1rem; transition: transform .25s ease, background-color .25s ease; }
.motion-card:hover { transform: translateY(-4px); background: #bbf7d0; }
.code-sample { text-align: left; background: #111827; color: #e5e7eb; padding: 1rem; border-radius: 8px; overflow: auto; white-space: pre-wrap; }
@media (prefers-reduced-motion: reduce) { *, *::before, *::after { scroll-behavior: auto !important; transition-duration: .01ms !important; animation-duration: .01ms !important; } .motion-card:hover { transform: none; } }

const lessonTitle = "Focus Management & Trapping";
const form = document.querySelector('#a11yForm');
const email = document.querySelector('#studentEmail');
const emailError = document.querySelector('#emailError');
const errorSummary = document.querySelector('#errorSummary');
const formStatus = document.querySelector('#formStatus');
const menuButton = document.querySelector('#menuButton');
const menu = document.querySelector('#practiceMenu');
const dialog = document.querySelector('#lessonDialog');
const openDialog = document.querySelector('#openDialog');
const closeDialog = document.querySelector('#closeDialog');

form?.addEventListener('submit', event => {
  event.preventDefault();
  const validEmail = email.value.includes('@');
  email.setAttribute('aria-invalid', String(!validEmail));
  emailError.hidden = validEmail;
  errorSummary.hidden = validEmail;

  if (!validEmail) {
    errorSummary.textContent = 'Fix 1 error before continuing: enter a valid email address.';
    formStatus.textContent = '';
    errorSummary.focus();
    return;
  }

  errorSummary.textContent = '';
  formStatus.textContent = 'Accessibility check passed for ' + lessonTitle + '.';
});

menuButton?.addEventListener('click', () => {
  const open = menuButton.getAttribute('aria-expanded') === 'true';
  menuButton.setAttribute('aria-expanded', String(!open));
  menu.hidden = open;
});

openDialog?.addEventListener('click', () => {
  dialog.showModal();
  closeDialog.focus();
});

closeDialog?.addEventListener('click', () => dialog.close());
dialog?.addEventListener('close', () => openDialog.focus());