Amazingly, I cannot find any solutions that aren't hacks into the keyup event, and even those don't worry. I am stunned that I cannot in native HTML5 just restrict an input from having more than two decimals.
For example, after I filled in a number input with (10.22) if I typed another number, nothing would happen. I have not found anything on StackOverflow, is this seriously a "yet-to-be-solved" thing, since I can't find a good solution online?