wcag-audit-operable-motion-test（WCAG 审核 operable motion 测试）

When to Use

Use this tool when implementing animations, transitions, or moving content to ensure compliance with motion sensitivity guidelines and respect for user reduced motion preferences.

Usage

Command Line

node scripts/test.js --duration 3.5 --type parallax
node scripts/test.js --duration 2.0 --flashes 5 --reduced-motion true
node scripts/test.js --json '{"duration": 4.2, "type": "scroll", "flashes": 0}'

JSON Input

node scripts/test.js --json '{
  "duration": 3.5,
  "type": "carousel",
  "flashes": 0,
  "userPrefersReducedMotion": true
}'

Parameters

• --duration: Animation duration in seconds
• --type: Animation type (scroll, parallax, carousel, transition, etc.)
• --flashes: Number of flashes per second (default: 0)
• --reduced-motion: Whether to simulate reduced motion preference (true/false)
• --json: JSON input with animation properties

Output

Returns JSON with compliance assessment and recommendations:

{
  "animation": {
    "duration": 3.5,
    "type": "parallax",
    "flashes": 0
  },
  "compliance": {
    "reducedMotion": true,
    "flashing": true,
    "duration": false
  },
  "issues": ["Animation duration exceeds 5 seconds"],
  "recommendations": [
    "Provide option to pause or disable parallax scrolling",
    "Consider using reduced motion alternative"
  ]
}

Examples

Test short animation

$ node scripts/test.js --duration 2.0 --type transition
✅ Reduced motion: RESPECTED
✅ Flashing: PASS (no flashes detected)
✅ Duration: PASS (2.0s within limit)
Animation meets accessibility requirements

Test long animation

$ node scripts/test.js --duration 8.5 --type carousel
⚠️  Reduced motion: NEEDS ATTENTION
✅ Flashing: PASS (no flashes detected)
❌ Duration: FAIL (8.5s exceeds 5s limit)
Recommendations:
- Provide pause/stop controls for auto-advancing carousel
- Consider shorter transition duration or user control
- Offer static alternative when reduced motion is preferred

Test flashing content

$ node scripts/test.js --duration 1.0 --flashes 4
✅ Reduced motion: RESPECTED
❌ Flashing: FAIL (4 flashes/s exceeds 3 flashes/s limit)
❌ Duration: PASS (1.0s within limit)
Recommendations:
- Reduce flashing frequency to maximum 3 flashes per second
- Consider non-flashing alternatives
- Test with users sensitive to flashing content

WCAG Standards

• Reduced Motion: Respect prefers-reduced-motion user preference
• Flashing Limit: Maximum 3 flashes per second
• Auto-play Duration: Moving content should be pausable within 5 seconds
• User Control: Provide options to pause, stop, or hide moving content
• Alternatives: Offer static alternatives for animated content

Animation Types

Safe Types

• Fade transitions: Gradual opacity changes
• Slide transitions: Smooth position changes
• Scale transforms: Size changes without movement

Risk Types

• Parallax scrolling: Multiple layers moving at different speeds
• Auto-advancing carousels: Content that changes automatically
• Flashing elements: Rapid visibility changes
• Spinning animations: Rotational movement

Best Practices

1. Check user preferences: Always respect prefers-reduced-motion
2. Provide controls: Allow users to pause/stop animations
3. Limit duration: Keep auto-playing content under 5 seconds
4. Avoid flashing: Never exceed 3 flashes per second
5. Test alternatives: Ensure functionality without animation

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