EVE Online has always had what we call the "in-game browser". It used to be this rather terrible system that was a custom built environment that had maybe 15 HTML tags supported. It was not a very good system.
Eventually, CCP made a deal with someone (I forget which framework they went with, I want to say it's webkit based?) and they embedded a modern browser with JavaScript support.
They've also done some modifications of the system -- when you are in-game, you can instruct your browser to "trust" the remote web site. If you do that, the browser starts sending along headers that include information like your location in-game, your character name/ID, what corporation you're in, etc. It's a rather abysmal system of authentication, but it works OK for basic things.
They also added some JavaScript APIS so you can do some things in-game from the browser. I.e., display "show info" windows, do some UI stuff, etc. This makes you able to build web sites that are slightly more interactive and useful and actually connect with the game you're playing.
The ERP we've built is, unfortunately for me, in .NET. It's an ASP.NET system (maybe C#?) and so I can't really work on it. (I'm a Perl/Python/Go guy mostly.) I have built some other systems that my corporation and alliance uses, though, that are not part of our ERP or EMC (corporation management application).
A screenshot of the production view of our ERP:
http://xb95.com/pics/eve-erp.png
Note that it has order priority, build location, item, quantity. The icons on the right allow the producer to handle the order -- "resources ordered" (turns out we didn't have it, so I had to order stuff), "build started" (it's in build, wait for it to finish), "buy instead" (turns out it's better to buy it, resubmit this to procurement), and cancel, comments, info, etc.
