Comment by lelandbatey

I always kinda figured that any "timer" in any language would technically need to work that way unless you're running a very fancy real-time system because multitasking, especially in high load scenarios, means there just may not be clock cycles available for your task at the exact millisecond you set something to execute at.

So it is with JS; I kinda figured EVERYTHING would need to be heavily throttled in a browser in order to respect the device running that browser.