Projects like EaglerForge allow you to inject JavaScript-based mods directly into the game. Open your compiled Eaglercraft client. Click the "Mods" button in the main menu.
: A popular Optifine-style client specifically for Eaglercraft that focuses on performance enhancements and visual tweaks . Available Mod Features mods for eaglercraft
Go to Options > Resource Packs and upload your .zip or .epk file directly from your computer. mods for eaglercraft