Is there any part of the spec that prevents a 120 Hz iPad Pro from having 120fps requestAnimationFrame? [closed]

Question

I just ran MrDoob's FPS counter on Safari in a new Apple's iPad Pro (120Hz) but it only runs at 60fps, whereas a Chrome browser in a desktop monitor (with a refresh rate of 144Hz) runs up to 144fps.

The script uses requestAnimationFrame to calculate them, so it's not technically a resource-intensive consumption.

I couldn't find it on the WHATWG specification, but seems it should. References:

1. IE https://connect.microsoft.com/IE/feedback/details/794072/internet-explorer-animations-fails-on-120hz-computer-monitors-works-at-60hz-75hz-100hz
2. http://www.testufo.com/browser.html
3. Related: https://github.com/w3c/html/issues/785

Tawnyatawsha

I discovered a few years ago some browsers restrict the speed requestanimationframe can run. But only some, meaning you can't rely on it. – Lacrimator

@TrevorD the question is why, couldn't find any on the docs. – Tawnyatawsha

If I had to guess, to save battery and prevent your phone from catching fire by running a simple loop at crazy framerates. – Lacrimator

@TrevorD not a loop, requestAnimationFrame. It renders based on device availability. – Tawnyatawsha

It's basically a loop. The browser restricts the speed so you can't run a phone at 600fps flashing a single image, causing the GPU to overheat and damage the phone, or kill battery life. – Lacrimator

Founder of TestUFO here. Apple is currently in violation of compliance of the HTML 5.2 and HTML 5.3 specification, section 7.1.4.2. Since Apple forces Chrome to use the Safari engine, the restriction also applies to all web browsers installed on the 120 Hz iPads. Currently, FireFox, Chrome, Opera, and Edge (74+) are all compliant and even works at 240 Hz – Kalmuck

Also, Microsoft Edge is now in compliance of the HTML specification for requestAnimationFrame framerate: blurbusters.com/… – Kalmuck

This question should be reopened. – Tawnyatawsha

Agreed. I've given an official HTML specification answer. – Kalmuck