Test the webcam and take pictures and video.

Test the microphone levels and hear playback.

Test the speakers and adjust volume and panning.

Test the keyboard and see which keys are pressed.

Test the display for dead pixels and color uniformity.

Test mouse and multitouch input capabilities.

View any supported sensor data, such as battery and movement.

Test the GPU for WebGL rendering capabilities.

Perform computations to benchmark your CPU's performance.

Simulate memory usage and benchmark the performance.

Test read/write speeds to benchmark local storage.

Test browser notifications and permissions.

Check your public IP address and geolocation.

Test your browser's compatibility and security settings.

Test MIDI input and output devices with a basic synth and console.

Test game controller buttons, axes and vibration.