Quick answer
What this guide helps you determine
Place several fingers inside the bounded surface and compare observed contacts with browser-reported support.
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 multi-touch browser test counts contacts delivered inside a bounded surface. navigator.maxTouchPoints is a browser-reported capability, while the observed maximum depends on hardware, browser gestures, accessibility and where the fingers land.
Step-by-step method
- Open the page directly on the touch device and keep every finger inside the marked test area. Add one finger at a time, hold briefly, and watch contact markers and the simultaneous count.
- Repeat with a different finger order and rotate the device. Avoid edges and system navigation zones because the operating system may reserve those gestures before the page receives them.
- Compare the observed count with maxTouchPoints but do not require them to match in every gesture. Test the same contacts in a drawing or mapping app if a particular combination matters.
What to check first
Use these checkpoints to keep the comparison focused. Record the visible behavior rather than assigning a fault label too early.
- Keep all touches inside the test surface
- Add fingers one at a time
- Avoid reserved system gestures
How to read what you see
| Observation | What it can suggest | Useful next check |
|---|---|---|
| Count increases for each added finger | The browser received those simultaneous contacts. | Repeat across the central area. |
| Contacts near an edge disappear | A system navigation gesture may intercept them. | Move inward and compare. |
| One physical region misses every finger | A location-specific digitizer or accessory issue is possible. | Rotate and repeat, then compare another app. |
Common mistakes to avoid
- Do not press hard; capacitive screens need contact, not force.
- Do not count reserved system gestures as hardware failures.
- Do not use liquids or remove protectors unless the manufacturer says it is safe.
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, “Count increases for each added finger”—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
Why does maxTouchPoints say 10 but I observe fewer?
The value is a capability report; browser/system gestures and the test area can reduce delivered contacts.
Does pressure mean how hard I press?
Support varies, and many touchscreens report a generic or estimated value rather than calibrated force.
Primary technical references
The following specifications define the browser APIs discussed in this guide. They are primary web-platform references, not product repair manuals.