How to parse JavaScript from Zsh?

[TJ Luoma <luomat@xxxxxxxxx>]

Long story short… my home network is satellite Internet. It has a
20gb/month quota (not a typo). I used to be able to parse the output
of http://192.168.0.1 using `lynx` but they üpgraded their system and
now http://192.168.0.1 uses JavaScript to deliver the information.

I can't figure out how to parse JavaScript from a Zsh script.

Ok, I admit that this is skirting on the edge of Zsh here, but I've
been googling for a couple hours and don't seem to be finding anything
close to a solution. Maybe just haven't found the right keywords, but
I'm getting a ton of unrelated crap.

I'm guessing there's some tool out there like `lynx` or `wget` or
`curl` which can parse JavaScript from the command line, but I can't
find whatever it is.

So I'm hoping maybe someone here has already reached the top of this
mountain and can point me in the right direction.

TjL