How can I keep a Java-based pop-up open even when its parent page is closed?
I tried looking a the source, but the website developer has embedded the applet information inside a bunch of JavaScript.  Also, even if you had the jar(s), if the applet requires communication back to the server, it would be a real pain to get it running.


  For future reference, if they hadn't gotten all creative with the applet code, you could have simply run this command line:

$ appletviewer http://world87.runescape.com/



What I recommend is to create a dedicated Fluid App for the website.  It's super easy, just point Fluid at the base URL, and it creates a dedicated application wrapped around the website.  The coolest thing is that you can then simply launch your game directly from Applications.

Fluid is 100% free, and I am not affiliated with them in any way.