Here's how to go about it:
Pull up the developer tools that show you incoming and outgoing packets. On Chrome, you hit F12 and click Network, and Firefox has a similar thingy.
Post a single thing.The object of this is to see the session's unique id and verification key for you. This changes every time you enter the room. I'm pretty sure that you can get that value off of your entrance, but oh well.
Anyways, do that, and you'll send a POST packet, followed by a GET packet with your exact message in it. The GET one is the one you want. You can quickly filter through the packets to find the right one by looking in the Preview tab under Network on Chrome.
Scroll down to the bottom of the packet header where it talks about the Query String Parameters. Those are the things in the url with all the &'s after the .php. Yeah, you need those.
You need something that will send arbitrary packets to places. Postman for Chrome is a good choice. I'm sure there's something similar for Firefox. And maybe for Opera. Maybe AOL too, if you're thusly inclined.
Fill in the packet data.
You want to paste this into the field that says "Enter request URL here"
The URL params that say "FILL_ME_IN" need to be filled in with the info from step 3.
Down under form-data, there's 2 fields that need to be made.
_: [leave this value blank. i dont know why its here, or if it's even necessary, but do it anyways]
Send. You should get a response that looks like:
If you get something different, you did something wrong.