Here's an example of a simple text-based battlefield game like Free Fire, implemented as a single HTML file using JavaScript:
Battlefield Game
Please note that due to the limitations of the provided space, this game example is simplified and lacks visual elements and pictograms. It runs an infinite while loop, which may not be suitable for a real-time game on a smartphone. However, it demonstrates the basic logic of a simple battlefield game where the player attacks and the enemy attacks in turns, with health points being reduced until one side is defeated.