Code examples that accompany the MDN WebAssembly documentation — see https://developer.mozilla.org/en-US/docs/WebAssembly.
The examples can be tested locally by running a local server to serve your directory of choice.
If you modify any .wat files for testing you will need to generate a corresponding .wasm file, replacing the existing version in the folder.
This can be done using the wat2wasm tool, which is part of the WABT: The WebAssembly Binary Toolkit (for setup/usage see Converting the text .wat into a binary .wasm file on MDN and the readme in the WABT GitHub repo.
Note that some examples use features that are still considered optional.
These are listed in the supported proposals section on the WABT README.md, along with the flags used to invoke them.
For example, to build WASM for the multi-memory example you will need to specify the --enable-multi-memory flag as shown:
wat2wasm --enable-multi-memory multi-memory.wat