Loading the Emscripten module

Loading and interacting with a module that utilizes Emscripten's glue code is considerably different from WebAssembly's JavaScript API. This is because Emscripten provides additional functionality for interacting with the JavaScript code. In this section, we're going to discuss the loading code that Emscripten provides when outputting an HTML file and review the process for loading an Emscripten module in the browser.

Pre-generated loading code

If you specify -o <target>.html when running the emcc command, Emscripten generates an HTML file and automatically adds code to load the module to the end of the file. Here's what the loading code in the HTML file looks like with the contents of each Module function excluded:

var statusElement = document.getElementById('status');
var progressElement = document.getElementById('progress');
var spinnerElement = document.getElementById('spinner');

var Module = {
  preRun: [],
  postRun: [],
  print: (function() {...}...