Sure! Here's a simple tower defense game implemented as a single HTML file using JavaScript:
In this game, you would need to fill in the game logic, including enemy spawning, tower placement, shooting mechanics, collision detection, and win/lose conditions. The code provided above sets up the basic structure for a tower defense game, and you can further develop it according to your specific requirements.
Note that this is a simplified implementation, and you would need to add more gameplay elements, graphics, and features to make it a fully functional and enjoyable game.