Listening to an opened WebSocket and fetching incoming messages on the browser-side

I’m struggling with something about WebSockets and I can’t figure out why.

A bit more context

On this page, there is a Web Socket that is called “notify.bubble.is” that is provided by Bubble, a no-code tool that allows you to build web applications without code.

Existing Web Socket

I’d like to listen to the messages coming from the server (and especially one that is “has-last-change-flusk-privacy…”) and intercept them.

The problem

I tried several things in order to listen to this WebSocket :

  • Writing function ‘onmessage’ on the window.WebSocket object to log the message into the console (did not work)
  • Creating a new WebSocket and connect it to the same address as the existing one (wss://notify.bubble.is) but it receives no messages
  • Overriding prototype of window.WebSocket object to rewriting the ‘onmessage’ function (did also not work)
  • Adding an EventListener to the document with event ‘onmessage’ but it receives no messages

So I’m a bit confused…
I’m 99% sure there is a way to fetch these messages, and I think you guys could have wonderful and maybe out-of-the-box ideas (or maybe it’s very easy and I’m just so bad)!

If you need more details, more info, or anything… just ask and I’ll answer as soon as I can.
Thanks, guys! 🙂