Some browser can't access ws protocol under https

[m5horton]

Example is firefox

[m5horton]

This fixes firefox for this issue:
https://stackoverflow.com/questions/11768221/firefox-websocket-security-issue

No fix is available in Safari
https://stackoverflow.com/questions/45572440/how-to-access-an-insecure-websocket-from-a-secure-website

[fengliu00]

The solution for firefox: about:config->click conntinue->network.websocket.allowInsecureFromHTTPS->double click

[fengliu00]

Developers.aceinna.com doesn't support Safari.

[yiweisong]

I added a solution for Firefox and Safari.
The site will use wss protocol to listen message from python-openimu. And user should implement a websocket server that supports wss.

There is a tool about locally-trusted certificates, it helps to setup local wss server.
https://github.com/FiloSottile/mkcert

[m5horton]

Resolved for all except Safari.