Created attachment 470754 [details] setInterval test results for various platforms/browsers and conditions/modes For global function setInterval, the average delay detected may be 30% larger than the delay parameter value when Lower Power Mode is turned on or script runs in iframe. e.g. `setInterval(()=>{}, 66.66666666666667)` may actually scheduled at interval delay of 89ms. For average delay of setInterval implementations, I must adimit mobile Safari can make it very accurate in normal conditions, since Chrome just ignores fractional part of the delay parameter, and desktop Firefox has no self-regulation to ensure an accurate average delay. See demo [setInterval actual interval test](https://codepen.io/fuweichin/pen/PoayPbm) and attachment [setInterval test results for various platforms/browsers and conditions/modes].
<rdar://problem/126273114>