Sure, here's a simple example of a Magical Girls Fighting RPG game in a single HTML file, using JavaScript:
Magical Girls Fighting RPG
This HTML file sets up a canvas where the magical girl and an enemy are drawn as pink squares. Their names and health points are displayed above each square. The game begins with both characters with full health and takes turns attacking each other when the canvas is clicked. The battle ends when either character's health reaches 0, and a message is displayed accordingly.
Please note that this is a very basic example and can be expanded upon with additional features, graphics, and gameplay mechanics.