UserAgent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_11_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/55.0.2883.95 Safari/537.36

Steps to reproduce the problem:
1. Create a SharedArrayBuffer
2. Create a Int32Array of that buffer
3. On the main thread, call Atomics.wait() on that buffer

What is the expected behavior?
An exception is thrown.

What went wrong?
The main thread goes to sleep. Closing that tab becomes very difficult for novices.

Did this work before? No 

Does this work in other browsers? Yes

Chrome version: 58.0.2995.0  Channel: n/a
OS Version: OS X 10.11.6
Flash Version: Shockwave Flash 24.0 r0

The spec carved out a specific exemption allowing vendors to disallow blocking on specific threads, usually the main thread of a browser window. Certainly Chromium could decide they want to allow it, but I'm guessing you probably don't.

> Browsers will typically let agents that run on the browser's main thread have [[CanBlock]] equal to false, to prevent blocking the UI and to allow the main thread to do work on behalf of other threads.

Spec: http://tc39.github.io/ecmascript_sharedmem/shmem.html#WebBrowserEmbedding

Firefox Nightly 54.0a1 (2017-01-28) throws: "Error: waiting is not allowed on this thread"
 

Deleted: test.html 291 bytes

test.html 291 bytes View Download