KeyHandling

One day computers will be controlled with the power of our minds. Until that point in time, the main way of interacting with the computer is via the keyboard and mouse.

Keyhandling differs between browsers, therefore Gamma provides some convenience methods that the game developer can use to create keybindings that work across different browsers. This is provided by the gma.keyHandler object.

How to use it

The gma.keyHandler.register function allows you to register a function to be called, when a particular button is pressed.

Note

You need to register against a keycode – like ‘65’, rather than ‘a’ – so a list of common keycodes is listed at the end of this page.

When the button is pressed (or released), the function will be called with the event object that is generated by the keypress. This event object can used to determine whether the key was pressed or released.

gma.keyHandler.register(65, function(event) {
    if (event.type==="keyup") {
        alert('You pressed a');
    }
});

The keyHandler also has gma.keyHandler.reset and gma.keyHandler.numEvents functions. The gma.keyHandler.reset function can be used to remove all previously registered bindings and the gma.keyHandler.numEvents method will give you the number of bindings registered for a particular key.

// This will say 0 because nothing is registered for code 70 yet
alert(gma.keyHandler.numEvents(70));

// Set a binding for the 'e' button
gma.keyHandler.register(70, function(event) { alert('You pressed e');});

// Now it will say 1 because we just registered one
alert(gma.keyHandler.numEvents(70));

// Remove all currently registered bindings
gma.keyHandler.reset()

// And it will say 0 again, because we removed all the bindings
alert(gma.keyHandler.numEvents(70));

KeyCodes

Cursor Keys

Key	Code
Cursor Left	37
Cursor Down	40
Cursor Right	39
Cursor Up	38

KeyPad

Key	Code
0 -> 9	96 -> 105
.	110
Enter	13
/	111
*	106
-	109
+	107

Modifiers

Key	Code
Shift	16
Ctrl	17
Alt	18

Special Keys

Key	Code
BackSpace	8
Tab	9
Enter	13
Caps Lock	20
Esc	27
SpaceBar	32
Delete	46
Page Up	33
Page Down	34
End	35
Home	36
Insert	45
Windows Key	92
F1 -> F12	112 -> 123

Formatting

Key	Code
` and ~	192
- and _	189
= and +	187
\ and |	220

Numbers and Letters

Key	Code
0 -> 9	48 -> 57
a -> z	65 -> 90