Code Checker HTML JavaScript

The tool analyzes HTML and JavaScript code to identify syntax errors, unclosed tags, invalid attribute usage, and common JavaScript syntax issues. It runs entirely in the browser, avoiding server round-trips, and returns structured results that include severity, location, and suggested fixes. It supports standalone snippets and embedded code within larger documents.

Conceptually, the tool tokenizes and parses HTML separately from JavaScript, then performs cross-context checks where applicable (for example, ensuring script blocks reference valid IDs). It uses a rule-based engine to flag issues and aggregates findings into an issue list and a concise summary. Output is designed for both automation and quick debugging.

Beneficiaries include frontend developers validating edits, QA engineers performing quick checks in reviews, educators teaching HTML/JS fundamentals, and students learning syntax rules. Its unique value comes from in-browser operation, combined HTML and JavaScript coverage, and the ability to export results for tooling without installing local software.

Core features include HTML parsing with tag and attribute validation, JavaScript syntax checks, location-aware reporting (line and column), and a machine-readable results format. Typical use cases include validating code snippets, preparing teaching examples, or feeding into lightweight CI checks during development.