wrap
When does your counter wrap?
Pick the counter's width and what it counts. You get the time until it rolls over to zero, and, if you give a polling interval, how many wraps can fit between two samples. More than one means a difference between samples can't tell you what happened.
Runs entirely in your browser. Nothing you type is uploaded, logged or analysed, and the page's security policy stops it making network requests at all. How that works
Try
The worst case: a counter on a saturated link. A quieter link wraps more slowly, in proportion.
Width