UI 组件简单

Screen Reader Only Utilities

CSS utility classes and patterns for visually hidden content that remains accessible to screen readers and assistive technology.

在 Lab 中打开

css

目标: JS HTML

代码

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

body {
  font-family: "Inter", system-ui, -apple-system, sans-serif;
  background: #0a0a0a;
  color: #e4e4e7;
  line-height: 1.6;
  min-height: 100vh;
}

/* ==============================
   Screen Reader Only Utilities
   ============================== */

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

.sr-only-focusable:focus,
.sr-only-focusable:active {
  position: static;
  width: auto;
  height: auto;
  padding: 0.6rem 1.2rem;
  margin: 0;
  overflow: visible;
  clip: auto;
  clip-path: none;
  white-space: normal;
}

/* Reveal mode */
body.reveal-mode .sr-only:not(.sr-only-focusable) {
  position: static;
  width: auto;
  height: auto;
  padding: 0.15rem 0.4rem;
  margin: 0;
  overflow: visible;
  clip: auto;
  clip-path: none;
  white-space: normal;
  background: rgba(139, 92, 246, 0.15);
  color: #c084fc;
  border: 1px dashed rgba(139, 92, 246, 0.4);
  border-radius: 4px;
  font-size: 0.75rem;
  font-weight: 600;
}

body.reveal-mode .sr-reveal {
  display: flex !important;
}

/* ============================== */

.demo {
  max-width: 780px;
  margin: 0 auto;
  padding: 3rem 1.5rem;
}

.demo-title {
  font-size: 1.75rem;
  font-weight: 700;
  color: #fafafa;
  letter-spacing: -0.02em;
}

.demo-sub {
  color: #a1a1aa;
  margin-top: 0.25rem;
  font-size: 0.95rem;
}

/* Toggle Bar */
.toggle-bar {
  margin-top: 1.5rem;
  display: flex;
  justify-content: center;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.55rem 1rem;
  font-size: 0.825rem;
  font-weight: 500;
  font-family: inherit;
  border: 1px solid #27272a;
  border-radius: 8px;
  background: #18181b;
  color: #e4e4e7;
  cursor: pointer;
  transition: all 0.15s;
}

.btn:hover {
  background: #27272a;
}

.btn:focus-visible {
  outline: 2px solid #3b82f6;
  outline-offset: 2px;
}

.btn--reveal[aria-pressed="true"] {
  background: rgba(139, 92, 246, 0.15);
  border-color: rgba(139, 92, 246, 0.3);
  color: #c084fc;
}

/* Example Sections */
.example-section {
  margin-top: 2rem;
  background: #111113;
  border: 1px solid #27272a;
  border-radius: 12px;
  padding: 1.5rem;
}

.example-header {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  margin-bottom: 0.5rem;
}

.example-title {
  font-size: 1.05rem;
  font-weight: 600;
  color: #fafafa;
}

.example-badge {
  font-size: 0.65rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  padding: 0.15rem 0.5rem;
  border-radius: 100px;
}

.example-badge--green {
  background: rgba(34, 197, 94, 0.15);
  color: #4ade80;
  border: 1px solid rgba(34, 197, 94, 0.3);
}

.example-badge--blue {
  background: rgba(59, 130, 246, 0.15);
  color: #60a5fa;
  border: 1px solid rgba(59, 130, 246, 0.3);
}

.example-badge--amber {
  background: rgba(245, 158, 11, 0.15);
  color: #fbbf24;
  border: 1px solid rgba(245, 158, 11, 0.3);
}

.example-badge--purple {
  background: rgba(139, 92, 246, 0.15);
  color: #a78bfa;
  border: 1px solid rgba(139, 92, 246, 0.3);
}

.example-desc {
  font-size: 0.85rem;
  color: #a1a1aa;
  margin-bottom: 1rem;
}

.example-desc code {
  background: #1e1e22;
  padding: 0.1rem 0.35rem;
  border-radius: 4px;
  font-size: 0.78rem;
  color: #d4d4d8;
  font-family: "SF Mono", "Fira Code", monospace;
}

kbd {
  display: inline-block;
  padding: 0.08rem 0.4rem;
  background: #1e1e22;
  border: 1px solid #3f3f46;
  border-radius: 4px;
  font-size: 0.73rem;
  font-family: "SF Mono", "Fira Code", monospace;
  color: #d4d4d8;
}

.example-demo {
  background: #09090b;
  border: 1px solid #1e1e22;
  border-radius: 8px;
  padding: 1.25rem;
}

.example-hint {
  margin-top: 0.75rem;
  font-size: 0.78rem;
  color: #52525b;
  text-align: center;
}

/* Skip Link Demo */
.skip-link-demo {
  position: relative;
  min-height: 100px;
}

.skip-link {
  display: block;
  padding: 0.6rem 1.2rem;
  background: #3b82f6;
  color: #fff;
  text-decoration: none;
  font-weight: 600;
  font-size: 0.85rem;
  border-radius: 8px;
  z-index: 10;
  margin-bottom: 0.5rem;
}

.skip-link:focus {
  outline: 2px solid #60a5fa;
  outline-offset: 2px;
}

.fake-nav {
  display: flex;
  gap: 0.75rem;
  padding: 0.5rem 0.75rem;
  background: #18181b;
  border-radius: 6px;
  margin-bottom: 0.5rem;
}

.fake-nav-item {
  font-size: 0.78rem;
  color: #71717a;
}

.fake-main {
  padding: 1rem;
  background: #18181b;
  border-radius: 6px;
  font-size: 0.85rem;
  color: #52525b;
  text-align: center;
}

/* Icon Buttons */
.icon-buttons {
  display: flex;
  gap: 0.75rem;
  justify-content: center;
}

.icon-btn {
  width: 44px;
  height: 44px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: #18181b;
  border: 1px solid #27272a;
  border-radius: 10px;
  color: #a1a1aa;
  cursor: pointer;
  transition: all 0.15s;
  position: relative;
}

.icon-btn:hover {
  background: #27272a;
  color: #fafafa;
}

.icon-btn:focus-visible {
  outline: 2px solid #3b82f6;
  outline-offset: 2px;
}

/* Image Examples */
.image-examples {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
}

.image-card {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.5rem;
}

.image-placeholder {
  width: 100%;
  height: 100px;
  border-radius: 8px;
  display: flex;
  align-items: center;
  justify-content: center;
}

.image-placeholder--decorative {
  background: #18181b;
  border: 1px solid #27272a;
  color: #3f3f46;
}

.image-placeholder--info {
  background: rgba(59, 130, 246, 0.08);
  border: 1px solid rgba(59, 130, 246, 0.2);
  color: #60a5fa;
}

.image-type {
  font-size: 0.8rem;
  font-weight: 500;
  color: #d4d4d8;
}

.image-code {
  font-size: 0.7rem;
  color: #71717a;
  font-family: "SF Mono", "Fira Code", monospace;
  background: #1e1e22;
  padding: 0.15rem 0.4rem;
  border-radius: 4px;
}

/* SR Reveal */
.sr-reveal {
  display: none;
  align-items: flex-start;
  gap: 0.5rem;
  margin-top: 0.75rem;
  padding: 0.75rem;
  background: rgba(139, 92, 246, 0.08);
  border: 1px solid rgba(139, 92, 246, 0.2);
  border-radius: 8px;
}

.sr-reveal-label {
  font-size: 0.7rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: #a78bfa;
  white-space: nowrap;
  margin-top: 0.1rem;
}

.sr-reveal-text {
  font-size: 0.825rem;
  color: #c4b5fd;
  font-style: italic;
}

/* Techniques Grid */
.techniques-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 1rem;
}

.technique-card {
  background: #09090b;
  border: 1px solid #1e1e22;
  border-radius: 10px;
  padding: 1rem;
}

.technique-header {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  margin-bottom: 0.75rem;
}

.technique-status {
  font-size: 0.6rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  padding: 0.15rem 0.45rem;
  border-radius: 4px;
  flex-shrink: 0;
}

.technique-status--good {
  background: rgba(34, 197, 94, 0.15);
  color: #4ade80;
  border: 1px solid rgba(34, 197, 94, 0.3);
}

.technique-status--bad {
  background: rgba(239, 68, 68, 0.15);
  color: #f87171;
  border: 1px solid rgba(239, 68, 68, 0.3);
}

.technique-status--focus {
  background: rgba(59, 130, 246, 0.15);
  color: #60a5fa;
  border: 1px solid rgba(59, 130, 246, 0.3);
}

.technique-status--warn {
  background: rgba(245, 158, 11, 0.15);
  color: #fbbf24;
  border: 1px solid rgba(245, 158, 11, 0.3);
}

.technique-name {
  font-size: 0.85rem;
  font-weight: 600;
  color: #e4e4e7;
}

.technique-code {
  background: #111113;
  border: 1px solid #1e1e22;
  border-radius: 6px;
  padding: 0.65rem 0.85rem;
  overflow-x: auto;
  margin-bottom: 0.5rem;
}

.technique-code code {
  font-size: 0.72rem;
  font-family: "SF Mono", "Fira Code", monospace;
  color: #a1a1aa;
  line-height: 1.6;
  white-space: pre;
}

.technique-note {
  font-size: 0.78rem;
  color: #71717a;
  line-height: 1.5;
}

.technique-card--good {
  border-color: rgba(34, 197, 94, 0.15);
}

.technique-card--bad {
  border-color: rgba(239, 68, 68, 0.15);
}

.technique-card--warn {
  border-color: rgba(245, 158, 11, 0.15);
}

/* Scrollbar */
.technique-code::-webkit-scrollbar {
  height: 3px;
}

.technique-code::-webkit-scrollbar-track {
  background: transparent;
}

.technique-code::-webkit-scrollbar-thumb {
  background: #27272a;
  border-radius: 4px;
}

(() => {
  const toggleBtn = document.getElementById("toggle-reveal");

  toggleBtn.addEventListener("click", () => {
    const isRevealed = document.body.classList.toggle("reveal-mode");
    toggleBtn.setAttribute("aria-pressed", isRevealed ? "true" : "false");

    // Show/hide the sr-reveal panels
    document.querySelectorAll(".sr-reveal").forEach((el) => {
      el.hidden = !isRevealed;
    });
  });
})();

<!doctype html>
<html lang="en">
<head>
  <meta charset="UTF-8" />
  <meta name="viewport" content="width=device-width, initial-scale=1.0" />
  <title>Screen Reader Only Utilities</title>
  <link rel="stylesheet" href="style.css" />
</head>
<body>
  <div class="demo">
    <h1 class="demo-title">Screen Reader Only Utilities</h1>
    <p class="demo-sub">CSS patterns for visually hidden content that remains accessible to assistive technology.</p>

    <div class="toggle-bar">
      <button class="btn btn--reveal" id="toggle-reveal" aria-pressed="false">
        <svg xmlns="http://www.w3.org/2000/svg" width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><path d="M1 12s4-8 11-8 11 8 11 8-4 8-11 8-11-8-11-8z"/><circle cx="12" cy="12" r="3"/></svg>
        Reveal Hidden Content
      </button>
    </div>

    <!-- Skip Link -->
    <section class="example-section">
      <div class="example-header">
        <h2 class="example-title">Skip Link</h2>
        <span class="example-badge example-badge--green">sr-only-focusable</span>
      </div>
      <p class="example-desc">Invisible until focused via <kbd>Tab</kbd>. Lets keyboard users skip to main content.</p>
      <div class="example-demo">
        <div class="skip-link-demo">
          <a href="#main-content" class="sr-only sr-only-focusable skip-link">Skip to main content</a>
          <div class="fake-nav" aria-hidden="true">
            <span class="fake-nav-item">Logo</span>
            <span class="fake-nav-item">Home</span>
            <span class="fake-nav-item">About</span>
            <span class="fake-nav-item">Contact</span>
          </div>
          <div class="fake-main" id="main-content" aria-hidden="true">
            <span>Main Content Area</span>
          </div>
        </div>
        <div class="example-hint">Press <kbd>Tab</kbd> into this area to see the skip link appear</div>
      </div>
      <div class="sr-reveal" hidden>
        <span class="sr-reveal-label">Screen reader sees:</span>
        <span class="sr-reveal-text">"Skip to main content" (link)</span>
      </div>
    </section>

    <!-- Icon Buttons -->
    <section class="example-section">
      <div class="example-header">
        <h2 class="example-title">Icon Buttons with SR Labels</h2>
        <span class="example-badge example-badge--blue">sr-only</span>
      </div>
      <p class="example-desc">Icon-only buttons with visually hidden text labels for screen readers.</p>
      <div class="example-demo">
        <div class="icon-buttons">
          <button class="icon-btn" type="button">
            <svg xmlns="http://www.w3.org/2000/svg" width="20" height="20" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" aria-hidden="true"><path d="M11 4H4a2 2 0 0 0-2 2v14a2 2 0 0 0 2 2h14a2 2 0 0 0 2-2v-7"/><path d="M18.5 2.5a2.121 2.121 0 0 1 3 3L12 15l-4 1 1-4 9.5-9.5z"/></svg>
            <span class="sr-only">Edit item</span>
          </button>
          <button class="icon-btn" type="button">
            <svg xmlns="http://www.w3.org/2000/svg" width="20" height="20" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" aria-hidden="true"><polyline points="3 6 5 6 21 6"/><path d="M19 6l-1 14a2 2 0 0 1-2 2H8a2 2 0 0 1-2-2L5 6"/><path d="M10 11v6"/><path d="M14 11v6"/><path d="M9 6V4a1 1 0 0 1 1-1h4a1 1 0 0 1 1 1v2"/></svg>
            <span class="sr-only">Delete item</span>
          </button>
          <button class="icon-btn" type="button">
            <svg xmlns="http://www.w3.org/2000/svg" width="20" height="20" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" aria-hidden="true"><path d="M4 12v8a2 2 0 0 0 2 2h12a2 2 0 0 0 2-2v-8"/><polyline points="16 6 12 2 8 6"/><line x1="12" y1="2" x2="12" y2="15"/></svg>
            <span class="sr-only">Share item</span>
          </button>
          <button class="icon-btn" type="button">
            <svg xmlns="http://www.w3.org/2000/svg" width="20" height="20" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" aria-hidden="true"><path d="M20.84 4.61a5.5 5.5 0 0 0-7.78 0L12 5.67l-1.06-1.06a5.5 5.5 0 0 0-7.78 7.78l1.06 1.06L12 21.23l7.78-7.78 1.06-1.06a5.5 5.5 0 0 0 0-7.78z"/></svg>
            <span class="sr-only">Add to favorites</span>
          </button>
        </div>
      </div>
      <div class="sr-reveal" hidden>
        <span class="sr-reveal-label">Screen reader sees:</span>
        <span class="sr-reveal-text">"Edit item" (button), "Delete item" (button), "Share item" (button), "Add to favorites" (button)</span>
      </div>
    </section>

    <!-- Decorative vs Informative Images -->
    <section class="example-section">
      <div class="example-header">
        <h2 class="example-title">Decorative vs Informative Images</h2>
        <span class="example-badge example-badge--amber">alt text</span>
      </div>
      <p class="example-desc">Decorative images use <code>alt=""</code> and <code>aria-hidden="true"</code>. Informative images need descriptive alt text.</p>
      <div class="example-demo">
        <div class="image-examples">
          <div class="image-card">
            <div class="image-placeholder image-placeholder--decorative" role="img" aria-hidden="true">
              <svg xmlns="http://www.w3.org/2000/svg" width="32" height="32" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="1.5" stroke-linecap="round" stroke-linejoin="round"><rect x="3" y="3" width="18" height="18" rx="2" ry="2"/><circle cx="8.5" cy="8.5" r="1.5"/><polyline points="21 15 16 10 5 21"/></svg>
            </div>
            <span class="image-type">Decorative</span>
            <code class="image-code">alt="" aria-hidden="true"</code>
          </div>
          <div class="image-card">
            <div class="image-placeholder image-placeholder--info" role="img" aria-label="Bar chart showing monthly revenue increasing from $12k in January to $28k in June">
              <svg xmlns="http://www.w3.org/2000/svg" width="32" height="32" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="1.5" stroke-linecap="round" stroke-linejoin="round"><line x1="18" y1="20" x2="18" y2="10"/><line x1="12" y1="20" x2="12" y2="4"/><line x1="6" y1="20" x2="6" y2="14"/></svg>
            </div>
            <span class="image-type">Informative</span>
            <code class="image-code">alt="Bar chart showing..."</code>
          </div>
        </div>
      </div>
      <div class="sr-reveal" hidden>
        <span class="sr-reveal-label">Screen reader sees:</span>
        <span class="sr-reveal-text">Decorative: (skipped). Informative: "Bar chart showing monthly revenue increasing from $12k in January to $28k in June"</span>
      </div>
    </section>

    <!-- CSS Techniques Comparison -->
    <section class="example-section">
      <div class="example-header">
        <h2 class="example-title">CSS Techniques Comparison</h2>
        <span class="example-badge example-badge--purple">reference</span>
      </div>
      <p class="example-desc">Different CSS methods for hiding content and their effect on screen readers.</p>
      <div class="techniques-grid">
        <div class="technique-card technique-card--good">
          <div class="technique-header">
            <span class="technique-status technique-status--good">SR reads</span>
            <h3 class="technique-name">.sr-only (clip-rect)</h3>
          </div>
          <pre class="technique-code"><code>.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}</code></pre>
          <p class="technique-note">The gold standard. Content is invisible but accessible.</p>
        </div>

        <div class="technique-card technique-card--good">
          <div class="technique-header">
            <span class="technique-status technique-status--good">SR reads</span>
            <h3 class="technique-name">.sr-only (clip-path)</h3>
          </div>
          <pre class="technique-code"><code>.sr-only-alt {
  position: absolute;
  clip-path: inset(50%);
  width: 1px;
  height: 1px;
  overflow: hidden;
  white-space: nowrap;
}</code></pre>
          <p class="technique-note">Modern alternative using clip-path. Same result.</p>
        </div>

        <div class="technique-card technique-card--bad">
          <div class="technique-header">
            <span class="technique-status technique-status--bad">SR skips</span>
            <h3 class="technique-name">display: none</h3>
          </div>
          <pre class="technique-code"><code>.hidden {
  display: none;
}</code></pre>
          <p class="technique-note">Hides from everyone, including screen readers. Do not use for accessible hiding.</p>
        </div>

        <div class="technique-card technique-card--bad">
          <div class="technique-header">
            <span class="technique-status technique-status--bad">SR skips</span>
            <h3 class="technique-name">visibility: hidden</h3>
          </div>
          <pre class="technique-code"><code>.invisible {
  visibility: hidden;
}</code></pre>
          <p class="technique-note">Also hides from screen readers. Element still takes up space.</p>
        </div>

        <div class="technique-card technique-card--good">
          <div class="technique-header">
            <span class="technique-status technique-status--focus">Visible on focus</span>
            <h3 class="technique-name">.sr-only-focusable</h3>
          </div>
          <pre class="technique-code"><code>.sr-only-focusable:focus,
.sr-only-focusable:active {
  position: static;
  width: auto;
  height: auto;
  clip: auto;
  clip-path: none;
  white-space: normal;
  overflow: visible;
  margin: 0;
}</code></pre>
          <p class="technique-note">Extends .sr-only. Becomes visible when focused (skip links).</p>
        </div>

        <div class="technique-card technique-card--warn">
          <div class="technique-header">
            <span class="technique-status technique-status--warn">Depends</span>
            <h3 class="technique-name">aria-hidden="true"</h3>
          </div>
          <pre class="technique-code"><code>&lt;span aria-hidden="true"&gt;
  Decorative content
&lt;/span&gt;</code></pre>
          <p class="technique-note">Hides from screen readers but remains visually visible. Use for decorative elements.</p>
        </div>
      </div>
    </section>
  </div>

  <script src="script.js"></script>
</body>
</html>

A comprehensive reference of CSS techniques for hiding content visually while keeping it accessible to screen readers. Compares clip-rect, clip-path, and absolute positioning methods, and contrasts them with display:none and visibility:hidden which hide from assistive technology too.