Simple JavaScript listener for document editing

Is it possible to create a simple codimd client in JavaScript for browser usage?

**It's target would be as follows:**
You configure the JavaScript client with a codimd document url (for being executed in the browser). The client will connect to the codimd server like any of the editor instances. Main difference is, that the connection is not for editing, but just for listening (read only, no writing access, therefore no conflicts in editing processes). This listener will always be informed about changes like any other editor instance. That's all.

**What is it good for?**
It would be possible to process the current document data independently from the collaborative editing process. If someone has specific interests like this https://github.com/hackmdio/codimd/issues/1407 he would be able to build it by himself (including a live mode). The listener ist receiving the Markdown data, which could be forwarded to another library like markmap (https://github.com/dundalek/markmap).

**Is there something why this souldn't be possible?**
I hope this idea is not in conflict with other considerations (e.g. security). Where is the code for establishing the connections between client and server? Perhaps I would be able to do it by my own and to submit it.

Thanks for codimd, great way of thinking!