keyboard
The Option key influences what characters are inserted when pressing different keys.
For example, Option-k is ˚ and Option-Shift-k is .
Is it possible to modify these? Is it possible to, for example, make Option-Space insert an En-space? And if so, how would I go about doing such a thing?
In the "Input menu" in the menu bar (to switch on System Preferences -> Language and Text -> Show Input method in menu bar.. Make sure Keyboard and Character Viewer in Select Input Methods to use is selected)
And you have your cheat sheet.
You probably need to step a level further down the tree of software and hardware, to the level of KyRemap4MacBook - which acts as a filter between the physical keyboard and the keyboard events reported to MacOS.
The software keyboard map is an optional thing - software can intercept keyboard events at a level that bypasses it, if they wish, and it sounds like some of what the browser does with key binding is touching on that.
A lower level remapping may bypass that problem.
Best Answer
You can remap keys with Ukelele or Karabiner.
http://scripts.sil.org/ukelele
https://pqrs.org/osx/karabiner/