Modern browsers set the 'location' property on keyboard events when
the key is located in several places. The ALT key, for example, can be
either on the left or the right side of the keyboard.
This change uses the location to determine which Apple key to
activate, if it is available, and defaults to the old behavior if not.
Normally, F2 causes the browser to go full-screen, showing only the
Apple screen. However, in Chrome, the user can exit full-screen mode
by pressing ESC. Since ESC is used frequently on the Apple //e, this
limits the utility of full-screen mode.
To work around this problem, this change adds Shift-F2, which will
make the Apple fill the window without going full-screen. This allows
the user to go make the window full-screen in some other way, thus
enabling the use of the ESC key.
Note that the method used is almost entirely implemented in CSS, with
just a few lines of code to change the classes on some elements. This
may not be the best long-term way of implementing this feature.