CSS Selector Tester
CSS selector
HTML input
Summary
Matched preview
Matched elements
About CSS Selector Tester
CSS Selector Tester checks a selector against a block of HTML using the browser's native selector engine.
It is useful when debugging complex selectors, verifying attribute selectors, checking nested markup, or confirming what querySelectorAll would match.
How to use this tool
- Paste HTML into the HTML input field.
- Enter the CSS selector you want to test.
- Click Test selector to view matching elements, paths, and a highlighted preview.
Tips
- Use the specificity calculator when two matching selectors compete in the cascade.
- Invalid selectors are reported by the browser selector parser.
- The preview is sandboxed so pasted markup does not run scripts.
Related guides
Learn the workflow behind this tool and what to check next.
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How to debug API JSON responses
Format the response, confirm the HTTP status, validate the schema, and compare payload changes before changing application code.
CSS selector checks before using a query in production
Test selectors against representative markup so they match the intended elements without depending on fragile structure or capturing unrelated content.
Positive and negative matches
Include elements that should match, near misses that should not, repeated components, and empty or optional containers.
Dynamic document states
Check markup before and after client rendering, lazy loading, validation, navigation, and state-class changes.
Selector portability
Confirm support for :has(), namespace syntax, escaping, and nonstandard extensions in the exact browser or library that runs the query.
Stable hooks
Use purposeful classes or data attributes for scripts and tests instead of selectors tied to visual nesting or generated class names.
Privacy and usage
Built for quick checks without an account
Toolinix tools are designed for short developer tasks: paste a safe sample, inspect the result, copy what you need, and move on.
No login required
You can use the tools without creating an account, subscribing to a newsletter, or saving a workspace.
Local when possible
Formatters, generators, encoders, and text utilities generally run in your browser. Network diagnostics may need a server-assisted lookup to check public URLs, domains, or IPs.
Keep secrets out
Do not paste production passwords, private keys, access tokens, customer records, or regulated data into online tools unless your own security policy allows it.
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