Emscripten refers to the toolchain used to compile C and C++ down to asm.js or WebAssembly. The EMSDK is used to manage the tools in the toolchain and the corresponding configuration. This eliminates the need for complex environment setup and prevents issues with incompatible versions of tooling. By installing the EMSDK, we have all of the tooling we need (with the exception of the prerequisites) to use the Emscripten compiler. The following diagram is a visual representation of the Emscripten toolchain (with the EMSDK shown in dark gray):

Now that you have a better understanding of Emscripten and the EMSDK, let's move on to the installation process for the prerequisites.