CSS Selector Tester & Query Debugger
Test CSS selectors against custom HTML markup in real-time with instant match counts and DOM element highlighting.
Matched Elements Preview:
How to Use CSS Selector Tester
Configure Input & Parameters
Enter your target endpoint, pattern, or data payload in the input fields above.
Execute Real-Time Analysis
Click the action button or type to trigger client-side validation, testing, and processing instantly.
Inspect & Export Results
Review detailed status badges, response trees, and copy formatted output to your clipboard.
Frequently Asked Questions
What selectors are supported?
All standard CSS Level 1, 2, 3, and 4 selectors supported natively by your browser's `querySelectorAll()` engine (classes, IDs, child combinators, pseudo-classes like `:nth-child`).
100% Client-Side Privacy
All tests, tokens, queries, and payload processing run securely inside your browser. No sensitive credentials or data ever hit external servers.
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