Why can't websocket (apache, request via js) be upgraded?

Question

JavaScript

WebSocket connection to 'ws://site.com/ws' failed: Error during WebSocket handshake: Unexpected response code: 400
Error in browser console

ProxyRequests off
    <Proxy *>
            order deny,allow
            allow from all
    </Proxy>


    ProxyPass /ws/  ws://localhost:8080/ws
    ProxyPassReverse /ws/  ws://localhost:8080/ws

    DocumentRoot /var/www
    <Directory />
        Options FollowSymLinks
        AllowOverride None
    </Directory>
    <Directory /var/www/>
        Options Indexes FollowSymLinks MultiViews
        AllowOverride None
        Order allow,deny
        allow from all

        RewriteEngine on
        RewriteRule ^(.*)$ http://localhost:8080/$1 [P,L]


    </Directory>