辅助功能审核者

全面的 Web 辅助功能测试与合规性说明。

注意

  • 此库中的示例旨在提供灵感，建议进行相应调整，使其更特定于你的项目、语言和团队流程。
  • 如需获取社区提供的有关特定语言和场景的自定义指令示例，请参阅出色的 GitHub Copilot 自定义内容仓库。
  • 可以跨不同范围应用自定义指令，具体取决于要在其中创建自定义指令的平台或 IDE。 有关详细信息，请参阅“关于自定义 GitHub Copilot 聊天助手响应”。

以下示例展示了一个路径特定的 accessibility.instructions.md 文件（该文件仅适用于仓库中的 HTML 文件），并指导 GitHub Copilot 生成符合 WCAG 准则、可访问且非独占的 HTML。 有关路径特定的说明文件的详细信息，请参阅 为 GitHub Copilot 添加存储库自定义说明。

Text
---
applyTo: **/*.html
---

When generating code, ensure accessibility compliance by following these priorities:

## Semantic HTML First
- Use proper semantic elements: `<nav>`, `<main>`, `<section>`, `<article>`, `<header>`, `<footer>`
- Structure headings sequentially (h1 → h2 → h3, never skip levels)
- Use one `<h1>` per page with descriptive heading text

## Essential ARIA Requirements
- Add `alt` text to all images
- Label form inputs with `<label>` or `aria-label`
- Ensure interactive elements have accessible names
- Use `aria-expanded` for collapsible content
- Add `role`, `aria-labelledby`, and `aria-describedby` when semantic HTML isn't sufficient

## Keyboard Navigation
- All interactive elements must be keyboard accessible
- Provide visible focus indicators (minimum 2px outline)
- Include skip links: `<a href="#main">Skip to main content</a>`
- Use logical tab order that matches visual layout

## Color and Contrast
- Ensure 4.5:1 contrast ratio for normal text, 3:1 for large text
- Don't rely solely on color to convey information

## Quick Test Questions
- Can you navigate the entire interface using only Tab/Shift+Tab/Enter?
- Are all images and icons properly described?
- Can screen reader users understand the content and functionality?

## Screen Reader Compatibility

**Provide descriptive text for all non-text content:**
- Images: Use alt text that describes function, not just appearance
  - Good: `alt="Submit form"`
  - Avoid: `alt="Blue button"`
- Form inputs: Associate every input with a `<label>` element
- Links: Use descriptive link text
  - Good: "Download the accessibility report (PDF, 2MB)"
  - Avoid: "Click here" or "Read more"

**Announce dynamic content updates:**
- Use `aria-live="polite"` for status updates
- Use `aria-live="assertive"` for urgent notifications
- Update screen reader users when content changes without page reload

---

## Color and Contrast Requirements

**Meet these specific contrast ratios:**
- Normal text (under 18pt): Minimum 4.5:1 contrast ratio
- Large text (18pt+ or 14pt+ bold): Minimum 3:1 contrast ratio
- UI components and graphics: Minimum 3:1 contrast ratio

**Provide multiple visual cues:**
- Use color + icon + text for status indicators
- Add patterns or textures to distinguish chart elements
- Include text labels on graphs and data visualizations

---

## Testing Integration Steps

**Include these automated checks:**
1. Run axe-core accessibility scanner in CI/CD pipeline
2. Test with lighthouse accessibility audit
3. Validate HTML markup for semantic correctness

**Perform these manual tests:**
1. Navigate entire interface using only Tab and arrow keys
2. Test with screen reader (NVDA on Windows, VoiceOver on Mac)
3. Verify 200% zoom doesn't break layout or hide content
4. Check color contrast with tools like WebAIM Color Contrast Checker

---

## Form Design Standards

**Create accessible form experiences:**
- Place labels above or to the left of form fields
- Group related fields with `<fieldset>` and `<legend>`
- Display validation errors immediately after the field with `aria-describedby`
- Use `aria-required="true"` for required fields
- Provide clear instructions before users start filling out forms

**Error message format:**
```html
<input aria-describedby="email-error" aria-invalid="true">
<div id="email-error">Please enter a valid email address</div>
```

---

**Code Generation Rule:** Always include accessibility comments explaining ARIA attributes and semantic choices. Test code with keyboard navigation before suggesting it's complete.

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