How to test a keyboard
Focus the keyboard board and press each physical key once. A displayed key turns green after the browser receives it. The summary shows the latest key value, hardware-independent code, and number of distinct keys detected.
The compact layout covers common US keyboard positions. Additional international keys can still register in the summary even when they are not drawn.
Checking missed keys and rollover
Test suspected keys individually first. Then hold two or more keys to inspect simultaneous detection. If a combination fails while each key works alone, the limitation may be keyboard rollover or matrix ghosting rather than a broken switch.
- Repeat failures in another browser or USB port.
- Disconnect hubs and adapters when troubleshooting.
- Check whether the problem appears only in one application.
Browser limitations
Operating-system shortcuts, media keys, power keys, and vendor-specific controls may never reach a webpage. Their absence does not prove the key is defective. Follow the full process in how to test every keyboard key.