Ensure all IDs are unique
SkillWeb & browsingA skill for AI agents that checks web page markup for duplicate element IDs. It is used when reviewing templates, rendered HTML, or shared components, and validates the final browser-facing markup rather than just the source framework abstraction.
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Then ask your AI: use the Ensure all IDs are unique skill
Details
Instructions available. Your AI can read the instructions. Execution depends on the setup they require.
Account requirements not reviewed. Check the skill instructions before use; ahel provides instructions and does not run this skill.
No other account needed.
Have the templates, rendered HTML, or shared components you want reviewed available.
What your AI can do with it
- Detects duplicate element IDs in templates and rendered HTML
- Reviews shared components for ID uniqueness
- Validates final browser-facing markup, not just source code
- Works during template and HTML review
Getting started
- Have the templates, rendered HTML, or shared components you want reviewed available.
- Load the skill into your agent's available skills.
- Ask the agent to review the markup for unique IDs.
- Check the agent's findings and fix any duplicate IDs it reports.
What this skill tells your AI
The instructions your AI receives, as published by thedaviddias/front-end-checklist in skills/unique-id/SKILL.md and read by ahel’s review.
Duplicate IDs break form accessibility (labels don't connect), ARIA relationships fail, and JavaScript getElementById returns wrong elements—causing silent bugs.
Quick Reference
- Each ID must appear only once per HTML document
- Use classes for styling, IDs for unique anchors/references
- Check for duplicates introduced by component libraries
- Duplicate IDs break form labels, ARIA, and getElementById
Check
Scan this HTML document to ensure all ID attributes are unique across the entire page and properly reference related elements.
Fix
Remove duplicate ID values, ensure each ID is used only once per page, and update any references like labels, ARIA attributes, or JavaScript selectors.
Explain
Explain why unique IDs are essential for HTML validity, accessibility (form labels, ARIA), JavaScript functionality, and CSS styling.
Code Review
Review templates, server-rendered HTML, and shared components that output markup related to Ensure all IDs are unique. Flag exact elements, attributes, and routes where the rendered HTML violates the rule.
For full implementation details, code examples, and framework-specific guidance,
see references/rule.md.
Rule page: https://frontendchecklist.io/en/rules/html/unique-id
Signals
- GitHub stars
- 74k
- Forks
- 7k
- Last commit
- Oct 2026
Questions
- What does this skill check for?
- It checks that every element ID in your web page markup is unique, so no ID is repeated across the page.
- Does it inspect source code or rendered output?
- It validates the final browser-facing markup, not just the source framework abstraction.
- When should it be used?
- When reviewing templates, rendered HTML, or shared components related to ensuring all IDs are unique.
Advanced
- Item type
- skill
- Key
unique-id- Source
- github.com/thedaviddias/front-end-checklist
github.com/thedaviddias/front-end-checklist
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