… well, that’s one encoding of the UTF-8 encoding of the Unicode code point.
> This is because setInterval(_=>{ },99) executes the function every 99ms
This is categorically wrong. You can’t trust setInterval to heed your request precisely at all: it’s a request that browsers take as a minimum only. Most browsers will call your function after the number of milliseconds you requested plus up to 16ms more, but some might wait even more than that (I think Safari in power saving mode doubles its tick time, to operate at 30fps; and background tabs typically won’t fire more than once a second these days).
Try running this snippet in your dev tools; it logs the number of milliseconds between calls:
t=Date.now();setInterval(()=>console.log(-t+(t=Date.now())), 99)
(Some trivia on similar techniques for this measurement: `+new Date` is rather slow, `Date.now()` is about 7× faster in at least Firefox and Chrome, and `performance.now()` gets you microsecond precision (it returns a floating-point number in milliseconds, tied to an unspecified epoch instead of real-world time), and is a little slower than Date.now().)