Our Free JS Version Checker provides a professional, high-performance solution to check your browser's supported JavaScript version, active ES engine features, and syntax capabilities instantly offline directly within your browser. Engineered for maximum speed and absolute privacy, the tool operates entirely on the client side using secure local JavaScript processing—meaning your data never leaves your device and is never uploaded to any external server. Whether you are working on a desktop, tablet, or mobile phone, the responsive and premium interface delivers instant real-time results with zero wait times. Designed for daily productivity, it features fully configurable parameters, robust input verification, and offline capability to ensure a seamless, secure workflow.
The engine triggers tests on script parsing capability automatically.
Review the generated list detailing support from ES5 to ES2024.
Review the generated diagnostic metrics and security ratings locally.
Simulates VPN WebRTC routing anomalies, checks active network IP addresses, and inspects CPU core allocations.
Configure testing variables—specify geolocation overrides, set range thresholds, and toggle device diagnostic features dynamically.
All hardware permissions and storage audits remain strictly local. Absolutely no diagnostic telemetry is transmitted to third parties.