You must prioritize simplicity. You and I are not smart enough to be clever, so don’t try. As the old saying goes, there are two kinds of programs: those simple enough to obviously have no bugs, and those complicated enough to have no obvious bugs. It is by no means easier to make the simpler kind, in fact, it’s much more difficult. However, the simpler the system is, the easier it is to reason about all of its states and edge cases. You do not need a JavaScript-powered custom textbox widget.