Sure! Here's an example of a simple jump game in a single HTML file using JavaScript.
This game creates a simple canvas where a player (represented by a black square) can jump. The player can jump by tapping the screen or pressing any key on the keyboard. The game includes a ground (represented by a gray rectangle) where the player lands after jumping.
Please note that this is a basic example and can be further expanded upon with additional mechanics, levels, or obstacles based on your needs.