Sure! Here's an example of a basic HTML file that contains JavaScript code for a simple open-world RPG game, inspired by Ultima Online. Please note that this is just a starting point, and you can expand and customize the game as per your requirements.
This code sets up a basic game canvas and initializes a player and an NPC (non-player character) as instances of the `Character` class. The `draw` method is used to render the characters on the canvas. You can expand upon this code by adding more game logic, such as movement, combat, quests, etc., to create a richer open-world RPG experience.
Feel free to modify and enhance this code to suit your game's specific requirements.