Sure! Here's a simple text-based FNAF (Five Nights at Freddy's) game implemented as a single HTML file using JavaScript:
Welcome to Five Nights at Freddy's
Survive five nights as a security guard at Freddy Fazbear's Pizza!
Please note that this is a simplified version of the game and doesn't include any actual gameplay mechanics or graphics. It only demonstrates the basic structure and logic flow of the game. You can further enhance it by adding more features and graphics as per your requirements.