Making a character jump (help please)

Question

Hello,
I have to make my character jump. Here is part of my code so far:
function handleKey(keyCode) {

if (keyCode == "ArrowUp") {
game.handleMove(0, -1);
}

}
The thing is I should use another variable and I have no idea of how to do it because every time I tried my character could only move on the left and right. Can someone show me an example of how I can do it?