Touch Start Counter

How the Touch Start Counter Works

Count the moment a finger first touches the pad. Each new touch adds one start event. Moving a finger or lifting it does not add a start.

1. Touch the surface: Each new finger contact fires one start event.
2. Add more fingers: Every extra finger fires its own start event, even while other fingers stay down.
3. Ignore releases: Lifting a finger does not change the count.
4. Check the event log: The log lists each start with its pointer ID, type and timestamp.

Touch Start Counter Formula

The total is the number of start events the browser sends. Count each new finger once.

touchstart

Event fired when contact begins

changedTouches.length

Number of new contacts in one event

Example: One touchstart event carries 2 new fingers, and a later event carries 1 finger. Total = 2 + 1 = 3 starts.

Touch Start Counter Reference Table

This table lists the start event names for a finger, pen, mouse and keyboard.

About the Touch Start Counter

A start event marks the first contact from a finger, pen or mouse button. This count helps you check input events.

Once all fingers lift, starts should equal ends plus cancels. A gap can be a clue that an event was lost. Check the logs to find out why.

Ways to Use the Touch Start Counter

Use start counts to check new contacts and test input. Here are five common uses.

• ✓Event debugging: Developers confirm each contact fires exactly 1 start event.
• ✓Input latency tests: Testers measure time from contact to the start event.
• ✓Multi-touch checks: Technicians confirm each added finger fires a new start.
• ✓Teaching web APIs: Instructors show the touchstart and pointerdown events live.
• ✓Ghost-touch logs: Users catch start events with no finger on the screen.