Sure! Here's an example of a simple Flappy Bird game implemented as a single HTML file using JavaScript. The game will run in a web browser, including smartphones.
To play the game, you need to open this HTML file in a web browser, either on a smartphone or desktop. The game works by tapping the screen (touching) or pressing a key (keypress) to make the bird jump. The goal is to avoid colliding with the green pipes. Your score will increase as you pass through each pair of pipes. If the bird collides with a pipe, the game ends, and your score will be displayed in an alert box.
Please note that this is a very basic implementation of Flappy Bird using plain JavaScript and HTML canvas. You can enhance this game by adding better graphics, sounds, and more features as per your requirements.