By now, you're probably getting unhappy about how unresponsive these games are to the keyboard.

They're really no better than Scratch.

The problem is we're relying on the key-repeat function of the keyboard.

You've doubtless noticed this, even just when typing documents. If you press a key and hold it down, one character immediately appears on the screen, then there's a delay, then the character starts to slowly repeat. This behaviour is controlled deep down in the operating system.

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Even worse, there can only be one key down at a time. For any decent game, you want to be able to press "up" and "right", and end up with a diagonal. Or hold down "right" and press the space bar at the same time.

Fortunately, with Javascript, we can do something about it.