Detecting Double-press Of A Key

I want to detect the double-press of the space key. However, I want a single press of a space key to have a different function. The double-tap of space should only count if the taps of space are no more than, say, a half second apart.

For example: The user hits space once, and javascript begins performing one action. 1/3rd of a second later, they hit the space bar again, and since that is within our threshold of 1/2 of a second, the action that began because the user hit the spacebar once should be cancelled, or undone (which I can write later) and the action when the user hits the spacebar twice should begin.