Just some arbitrary JS daftness to enhance* standard HTML text inputs.
Type some text in these here boxes to see this thing in action. Try deleting text too. Splat!
(*If by "enhance" you mean "Totally breaks accessibility and is generally awful UI but why not, eh?")
This might run very slowly in some browsers, might not work at all in others (doesn't work in IE10 and below. I'm not debugging that nonsense) and is also very stupid. Please don't use it in any production environments. Please. Though if you do actually have a genuine use for this, please let me know. I'd be very impressed.