KeyTrap.js

This script lets you intercept document-level keys, without
completely breaking everything, allwhere, everywhen: it sets
up intercepts for specific keys for specific elements, and
only intercepts these keys when focus is on the indicated
element. If focus is moved off of that element, key interceptions
bound to that element are completely ignored.

This is very useful for things like browser games, or custom
interaction elements, where something like "backspace" should,
under no circumstances make the browser jump to the previous
page. Similarly you can trap cursor keys, or the tab key, or
what have you. And because the trapping is per element, your
page won't break user interaction when the user is not focussed
on your browser-behaviour-modifying element.

(c) Mike "Pomax" Kamermans, 2011

You are permitted to use this package however you see
fit, except when that use interferes with the user's
expectations of browser interaction. So basically
"free to use, but if you're abusing this, you violated
the license agreement". Nice and simple.