Use this check to inspect a browser, device, network, permission, media, or input capability directly in the current runtime before relying on it in another workflow.

Key event log

Chronological key-event log from the surface.

Measure maximum simultaneous held keys from a key-event log to classify rollover support. The tool evaluates the supplied inputs together and returns the named outputs below; it does not infer omitted operating conditions or change the units shown.^[1]

Max concurrent keys

Largest number of simultaneously held keys.

Rollover class

Rollover classification of the probe.

Event count

Number of processed key events.

• Results describe the current browser session and can change with permissions, privacy controls, hardware, drivers, network path, power state, or browser updates. Unsupported or withheld information is not proof that the underlying capability is absent.
• Use finite inputs in the displayed units and preserve more precision than the final presentation requires. Independently verify safety-critical, financial, compliance, or production decisions.

Repeat the check in the browser and device that will actually be used, then confirm important behavior with the relevant operating-system or network diagnostics. Avoid granting permissions that are unnecessary for the test.

• Device Info Checker

  Normalize and classify a device descriptor probe into tiers, form factor, and identification confidence.

• GPU Info Checker

  Classify a GPU probe into vendor, model token, and integrated versus discrete hints.

• Media Support Checker

  Summarize codec probe results into playback readiness with coverage and gaps.