Accessibility Using only Javascript

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<script nomodule src="https://unpkg.com/ionicons@7.1.0/dist/ionicons/ionicons.js"></script>

<a href="#main-content" class="skip-link">Skip to main content</a>

<div class="container" id="main-content">
  <h1>JavaScript Accessibility Demo</h1>
  <p class="subtitle">Best practices for building accessible web applications</p>

  <!-- 1. Keyboard Navigation -->
  <div class="demo-section">
    <h2>
      <ion-icon name="keypad-outline"></ion-icon>
      Keyboard Navigation
    </h2>
    <p class="feature-description">Custom button with full keyboard support (Enter/Space)</p>
    <button class="custom-btn" id="keyboardBtn">
      <ion-icon name="hand-left-outline"></ion-icon>
      Click or Press Enter/Space
    </button>
  </div>

  <!-- 2. Form Validation -->
  <div class="demo-section">
    <h2>
      <ion-icon name="checkmark-circle-outline"></ion-icon>
      Accessible Form Validation
    </h2>
    <p class="feature-description">Real-time validation with ARIA attributes</p>
    <form id="accessibleForm">
      <div class="form-group">
        <label for="username">Username (required)</label>
        <input 
               type="text" 
               id="username" 
               name="username"
               aria-required="true"
               aria-describedby="username-error"
               aria-invalid="false"
               >
        <div id="username-error" class="error-message" role="alert">
          <ion-icon name="alert-circle-outline"></ion-icon>
          <span>Username must be at least 3 characters</span>
        </div>
      </div>
      <div class="form-group">
        <label for="email">Email (required)</label>
        <input 
               type="email" 
               id="email" 
               name="email"
               aria-required="true"
               aria-describedby="email-error"
               aria-invalid="false"
               >
        <div id="email-error" class="error-message" role="alert">
          <ion-icon name="alert-circle-outline"></ion-icon>
          <span>Please enter a valid email address</span>
        </div>
      </div>
      <button type="submit" class="custom-btn">
        <ion-icon name="paper-plane-outline"></ion-icon>
        Submit Form
      </button>
    </form>
  </div>

  <!-- 3. Live Region -->
  <div class="demo-section">
    <h2>
      <ion-icon name="notifications-outline"></ion-icon>
      ARIA Live Regions
    </h2>
    <p class="feature-description">Dynamic content announcements for screen readers</p>
    <div class="live-region-demo">
      <button class="custom-btn" id="liveRegionBtn">
        <ion-icon name="refresh-outline"></ion-icon>
        Update Status
      </button>
      <div id="statusMessage" class="status-message" role="status" aria-live="polite">
        <ion-icon name="checkmark-circle"></ion-icon>
        <span>Status updated successfully!</span>
      </div>
    </div>
  </div>

  <!-- 4. Focus Management -->
  <div class="demo-section">
    <h2>
      <ion-icon name="scan-outline"></ion-icon>
      Focus Trap (Modal)
    </h2>
    <p class="feature-description">Proper focus management in modal dialogs</p>
    <button class="custom-btn" id="openModalBtn">
      <ion-icon name="open-outline"></ion-icon>
      Open Modal
    </button>
  </div>
</div>

<!-- Modal -->
<div class="modal" id="modal" role="dialog" aria-labelledby="modal-title" aria-modal="true">
  <div class="modal-content">
    <h3 id="modal-title">Accessible Modal</h3>
    <p>Focus is trapped within this modal. Press Tab to cycle through focusable elements, or Escape to close.</p>
    <div class="modal-actions">
      <button class="custom-btn" id="modalAction">
        <ion-icon name="checkmark-outline"></ion-icon>
        Confirm
      </button>
      <button class="btn-secondary" id="closeModalBtn">
        <ion-icon name="close-outline"></ion-icon>
        Close
      </button>
    </div>
  </div>
</div>

     * {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
        }

        body {
            font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
            background: #f5f5f5;
            padding: 40px 20px;
            line-height: 1.6;
        }

        .container {
            max-width: 800px;
            margin: 0 auto;
            background: white;
            padding: 40px;
            border-radius: 8px;
            box-shadow: 0 2px 10px rgba(0,0,0,0.1);
        }

        h1 {
            color: #2c3e50;
            margin-bottom: 10px;
            font-size: 28px;
        }

        .subtitle {
            color: #7f8c8d;
            margin-bottom: 30px;
            font-size: 14px;
        }

        .demo-section {
            margin-bottom: 40px;
            padding-bottom: 40px;
            border-bottom: 1px solid #ecf0f1;
        }

        .demo-section:last-child {
            border-bottom: none;
        }

        h2 {
            color: #34495e;
            margin-bottom: 15px;
            font-size: 20px;
            display: flex;
            align-items: center;
            gap: 10px;
        }

        .feature-description {
            color: #7f8c8d;
            margin-bottom: 20px;
            font-size: 14px;
        }

        /* Custom Button with Keyboard Support */
        .custom-btn {
            background: #3498db;
            color: white;
            border: none;
            padding: 12px 24px;
            border-radius: 6px;
            cursor: pointer;
            font-size: 16px;
            transition: all 0.2s;
            display: inline-flex;
            align-items: center;
            gap: 8px;
        }

        .custom-btn:hover {
            background: #2980b9;
            transform: translateY(-1px);
        }

        .custom-btn:focus {
            outline: 3px solid #3498db;
            outline-offset: 2px;
        }

        .custom-btn:active {
            transform: translateY(0);
        }

        /* Skip Link */
        .skip-link {
            position: absolute;
            top: -40px;
            left: 0;
            background: #2c3e50;
            color: white;
            padding: 8px 16px;
            text-decoration: none;
            border-radius: 0 0 4px 0;
        }

        .skip-link:focus {
            top: 0;
        }

        /* Accessible Form */
        .form-group {
            margin-bottom: 20px;
        }

        label {
            display: block;
            margin-bottom: 6px;
            color: #2c3e50;
            font-weight: 500;
        }

        input[type="text"],
        input[type="email"] {
            width: 100%;
            padding: 10px;
            border: 2px solid #ddd;
            border-radius: 4px;
            font-size: 16px;
            transition: border-color 0.2s;
        }

        input:focus {
            outline: none;
            border-color: #3498db;
        }

        .error-message {
            color: #e74c3c;
            font-size: 14px;
            margin-top: 5px;
            display: none;
        }

        .error-message.show {
            display: flex;
            align-items: center;
            gap: 5px;
        }

        /* Live Region */
        .live-region-demo {
            background: #ecf0f1;
            padding: 20px;
            border-radius: 6px;
        }

        .status-message {
            background: #27ae60;
            color: white;
            padding: 12px;
            border-radius: 4px;
            margin-top: 10px;
            display: none;
            align-items: center;
            gap: 8px;
        }

        .status-message.show {
            display: flex;
        }

        /* Focus Trap Demo */
        .modal {
            display: none;
            position: fixed;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
            background: rgba(0,0,0,0.5);
            justify-content: center;
            align-items: center;
            z-index: 1000;
        }

        .modal.show {
            display: flex;
        }

        .modal-content {
            background: white;
            padding: 30px;
            border-radius: 8px;
            max-width: 400px;
            width: 90%;
        }

        .modal h3 {
            color: #2c3e50;
            margin-bottom: 15px;
        }

        .modal-actions {
            display: flex;
            gap: 10px;
            margin-top: 20px;
        }

        .btn-secondary {
            background: #95a5a6;
            color: white;
            border: none;
            padding: 10px 20px;
            border-radius: 6px;
            cursor: pointer;
            font-size: 14px;
        }

        .btn-secondary:hover {
            background: #7f8c8d;
        }

        .btn-secondary:focus {
            outline: 3px solid #95a5a6;
            outline-offset: 2px;
        }

  // 1. Keyboard Navigation
        const keyboardBtn = document.getElementById('keyboardBtn');
        keyboardBtn.addEventListener('click', () => {
            alert('Button activated! This works with mouse, keyboard, and assistive technologies.');
        });

        // 2. Form Validation with ARIA
        const form = document.getElementById('accessibleForm');
        const username = document.getElementById('username');
        const email = document.getElementById('email');
        const usernameError = document.getElementById('username-error');
        const emailError = document.getElementById('email-error');

        function validateUsername() {
            if (username.value.length < 3) {
                username.setAttribute('aria-invalid', 'true');
                usernameError.classList.add('show');
                return false;
            } else {
                username.setAttribute('aria-invalid', 'false');
                usernameError.classList.remove('show');
                return true;
            }
        }

        function validateEmail() {
            const emailRegex = /^[^\s@]+@[^\s@]+\.[^\s@]+$/;
            if (!emailRegex.test(email.value)) {
                email.setAttribute('aria-invalid', 'true');
                emailError.classList.add('show');
                return false;
            } else {
                email.setAttribute('aria-invalid', 'false');
                emailError.classList.remove('show');
                return true;
            }
        }

        username.addEventListener('blur', validateUsername);
        email.addEventListener('blur', validateEmail);

        form.addEventListener('submit', (e) => {
            e.preventDefault();
            const isUsernameValid = validateUsername();
            const isEmailValid = validateEmail();
            
            if (isUsernameValid && isEmailValid) {
                alert('Form submitted successfully!');
                form.reset();
            } else {
                const firstInvalid = form.querySelector('[aria-invalid="true"]');
                if (firstInvalid) firstInvalid.focus();
            }
        });

        // 3. Live Region
        const liveRegionBtn = document.getElementById('liveRegionBtn');
        const statusMessage = document.getElementById('statusMessage');

        liveRegionBtn.addEventListener('click', () => {
            statusMessage.classList.add('show');
            setTimeout(() => {
                statusMessage.classList.remove('show');
            }, 3000);
        });

        // 4. Focus Trap in Modal
        const modal = document.getElementById('modal');
        const openModalBtn = document.getElementById('openModalBtn');
        const closeModalBtn = document.getElementById('closeModalBtn');
        const modalAction = document.getElementById('modalAction');
        let lastFocusedElement;

        function openModal() {
            lastFocusedElement = document.activeElement;
            modal.classList.add('show');
            closeModalBtn.focus();
            document.addEventListener('keydown', handleModalKeydown);
        }

        function closeModal() {
            modal.classList.remove('show');
            document.removeEventListener('keydown', handleModalKeydown);
            if (lastFocusedElement) lastFocusedElement.focus();
        }

        function handleModalKeydown(e) {
            if (e.key === 'Escape') {
                closeModal();
                return;
            }

            if (e.key === 'Tab') {
                const focusableElements = modal.querySelectorAll('button');
                const firstElement = focusableElements[0];
                const lastElement = focusableElements[focusableElements.length - 1];

                if (e.shiftKey && document.activeElement === firstElement) {
                    e.preventDefault();
                    lastElement.focus();
                } else if (!e.shiftKey && document.activeElement === lastElement) {
                    e.preventDefault();
                    firstElement.focus();
                }
            }
        }

        openModalBtn.addEventListener('click', openModal);
        closeModalBtn.addEventListener('click', closeModal);
        modalAction.addEventListener('click', () => {
            alert('Action confirmed!');
            closeModal();
        });

        modal.addEventListener('click', (e) => {
            if (e.target === modal) closeModal();
        });