Quick answer
What this guide helps you determine
A repeatable way to check alphanumeric keys, modifiers, navigation keys and the number pad without losing track of what you have tested.
Begin with the observable browser result, repeat it under the same conditions, and change one connection, setting or application at a time. A browser result narrows likely causes but does not certify hardware or decide a repair.
Scope of this check
A complete keyboard check is easier when the board is divided into zones. Start with letters and numbers, continue through modifiers and navigation keys, and finish with the function row and number pad. This prevents a bright on-screen keyboard from creating the false impression that every key has already been tested.
Step-by-step method
- Click the visual keyboard so the page has focus, then press and release one key at a time. Watch both the physical-position value (code) and the character value (key). A changed keyboard layout can alter key while code remains tied to the same standard position.
- Test left and right Shift, Control and Alt separately because they have distinct locations even when an application treats them alike. Turn Num Lock on and off before judging the keypad, and finish any IME composition before comparing a character result.
- After the single-key pass, try only the combinations you actually need, such as movement keys plus Shift or Control. Release every key between combinations and repeat a missing result in a plain text editor before recording it as a keyboard problem.
What to check first
Use these checkpoints to keep the comparison focused. Record the visible behavior rather than assigning a fault label too early.
- Test one keyboard section at a time
- Compare key and code when a label looks wrong
- Repeat the test in another app before blaming hardware
How to read what you see
| Observation | What it can suggest | Useful next check |
|---|---|---|
| The visual key changes on press and release | The browser received both transitions during this session. | Mark the key as observed and continue to the next zone. |
| code is expected but key shows another character | The physical switch likely worked; the active layout, modifier, Num Lock or IME changed the value. | Check the operating-system input language and remapping settings. |
| One physical key produces no event in two applications | Focus is less likely to be the cause; the connection, debris, switch or firmware needs comparison. | Reconnect the keyboard and test it on another port or computer. |
Common mistakes to avoid
- Do not type passwords or private messages into a diagnostic page.
- Do not count reserved operating-system shortcuts as failed keys when the browser never receives them.
- Do not remove keycaps or use liquid unless the manufacturer instructions allow it.
Build evidence another person can use
Write down the exact action, visible result and whether it repeats. Include the browser family, operating-system family, connection type and the single comparison that changed the result. Quote the observation directly—for example, “The visual key changes on press and release”—then add where it occurred and which comparison changed it.
Change one condition per comparison and return settings that have no effect. Follow model-specific manufacturer instructions before firmware changes, cleaning, disassembly or warranty action.
When to seek qualified support
If the same problem remains in multiple applications and on another compatible connection or computer, collect the repeatable observations and contact the manufacturer or a qualified technician. Stop using equipment that is physically damaged, unusually hot, wet, sparking or unsafe. Device Test Bench cannot inspect electrical condition or make a repair decision.
Privacy during testing
Our public tests process key events, pointer values, media streams and controller input locally. Do not send private recordings, complete typed text or device identifiers when asking for help. A short description of the behavior, browser and page URL is normally enough.
Questions readers ask
Do I need to test capital and lowercase letters separately?
Test the letter once, then verify each Shift key with a few letters. The switch is the same; the modifier state changes the character.
Why does the Windows or Command key leave the page?
Some system shortcuts are handled before the browser. Use a harmless press and observe it without completing a disruptive shortcut.
Primary technical references
The following specifications define the browser APIs discussed in this guide. They are primary web-platform references, not product repair manuals.