Fix #302

[vipcxj]

All test passed except some faild without my commit as well.

[danfickle]

Hi @vipcxj,

Firstly, huge thanks for contributing to this project and fixing this longstanding bug! The code looks excellent.

As you will see, I made a few minor changes:

• Moved your test to the automatic test runner that compares the result with known good proof.
• Added a nested test, just to make sure it works similar to Chrome. It does!

Thanks again! I'll merge as soon as the CI server says OK.