Because it runs on a browser, Eaglercraft X uses specialized technology to emulate the desktop experience:
One of the project's most popular aspects is its multiplayer capability: Eaglecraft X
(also known as Eaglercraft 1.8) is a community-driven, open-source project that allows a full version of Minecraft Java Edition to run directly within a web browser. Unlike a simple clone or a fan-made recreation, it is a direct port of the original Minecraft 1.8 code, compiled into JavaScript and WebAssembly using the TeaVM toolset. Because it runs on a browser, Eaglercraft X
Eaglercraft X brings the "Bountiful Update" (Minecraft 1.8.8) to the web, meaning it includes features that define the era of classic Java gameplay: Because it runs on a browser