CSS Selector Tester

How to use this developer tool

1. Paste source text or load the representative sample.
2. Adjust the available parsing option when the tool provides one.
3. Select Test Selector or press Ctrl/Cmd + Enter.
4. Review the summary, issues, and copy-ready output before using it.

What this developer tool does

The HTML fragment is parsed into an isolated document and queried with querySelectorAll. A stable, readable path is built from each matched element and its ancestors; no pasted scripts are executed.

Browser support determines which modern pseudo-classes can be tested. Dynamic states such as :hover and layout-dependent selectors cannot be simulated in static pasted HTML.

Example

Input

article.card > h2:first-child

<!-- HTML starts after the blank line -->
<main>
  <article class="card"><h2>First</h2><p>Body</p></article>
  <article class="card featured"><h2>Second</h2></article>
</main>

Expected result

Run the sample to see a structured report generated by the same processing logic used for pasted input.

Use cases

• Review front-end source during a code migration.
• Create a structured handoff for documentation or QA.
• Catch input-specific issues before committing generated output.

Tips for reliable output

• Paste the smallest complete fragment that reproduces the case.
• Use the sample once to confirm the expected input shape.
• Review warnings instead of treating a clean report as a guarantee.
• Keep the original source in version control before replacing it.
• Test generated output in the target browser or application.

Processing details

The HTML fragment is parsed into an isolated document and queried with querySelectorAll. A stable, readable path is built from each matched element and its ancestors; no pasted scripts are executed.

Browser support determines which modern pseudo-classes can be tested. Dynamic states such as :hover and layout-dependent selectors cannot be simulated in static pasted HTML.