Google Chrome places a restriction on what can be included in the body of a Web Worker's postMessage() function. If you tried to send a compiled WebAssembly.Module to a worker, you'd get an error and the operation would be unsuccessful. You can override this by setting a flag. To enable this functionality, open Google Chrome and enter chrome://flags in the address bar. Type cloning in the search box at the top of the page. You should see a list item titled WebAssembly structured cloning support. Select the Enabled option from the dropdown next to the list item and press the RELAUNCH NOW button when prompted:

After Chrome restarts, you can run the example application without issue. If you're using Mozilla Firefox, no action is required. It supports this feature by default. Let's move on to the example application that demonstrates the use of WebAssembly in threads.