Another thought: Eaglercraft uses WebGL for rendering, maybe? Or Canvas2D. If it's WebGL, then modifying shaders could alter visuals, but that's probably more advanced. For the user's purposes, simple movement or item hacks would be more useful.
If you want to create your own custom modifications or hacks: Hacks For Eaglercraft 1-5-2
: Only attacks when your crosshair is over a target. Movement Mods : Another thought: Eaglercraft uses WebGL for rendering, maybe
This means that memory injection (the standard method for Java Minecraft cheats) is impossible. Hack developers must instead modify the JavaScript source code or intercept network traffic. maybe? Or Canvas2D. If it's WebGL