Board Thread:Questions and Answers/@comment-24386245-20140806114104/@comment-5334617-20140806145351

Here's an outline for a simple type of "jump", assuming you already have 'fall' figured out.

Introduce a new variable, say. Initialize it to zero at the beginning of the game. When the player is standing on solid ground, and the 'jump' button is pressed, set  to, say, 10. Now, once per iteration through the superloop, when you check for the player falling, BEFORE checking for falling, first check if  is positive. If it is positive, move the sprite up the screen a little bit, and decrement. After several iterations,  will hit zero, and then the 'fall' check will kick in starting the next iteration.

The value you assign to, and the amount by which you move the player up each iteration, will determine how long the jump lasts and how high it goes.