That HTML you posted isn't telling you scripts are being blocked. The <noscript> means that's the text to be displayed in case JavaScript is disabled or otherwise not working.

If your browser is like my (older) Firefox, the pulldown menu under Tools should have an option for "Error Console"; I'm pretty sure it used to be called "JavaScript Error Console". Clicking on it shows me a huge long list of incidents that JavaScript (I think!) has encountered recently. Not that I understand what they're about, but almost all of the ones listed in mine seem to refer to trivial incidents (unable to find this, undefined that) that have produced no noticeable consequences for me. I'd expect yours (if it's even there) to look a lot like mine but if it happened to be complaining repeatedly about why it couldn't open a popup or something, that just might give you a lead. The most promising time to check it would probably be right after you'd tried and failed to get into chat.

I don't know exactly what the connection is between JavaScript and popups, but there does seem to be one. Back in the bad old days before Firefox, I found I could effectively block popups by keeping JavaScript permanently disabled except when I really needed some feature (like a "good" popup) that depended on it.