Sure! Here's an example of a simple football game implemented as a single HTML file using JavaScript:
In this example, a canvas element is used to draw and update the position of a ball representing the football. The ball moves around the canvas, bouncing off the walls. The game loop is established using the `requestAnimationFrame` method to continuously update the ball's position and redraw it on the canvas.
Note: This is a basic example and can be extended further to include game mechanics, scoring, player controls, and more visual elements.