Downloading JARs

I'm trying to download this java applet so's I can play it offline:

http://dan-ball.jp/en/javagame/dust/

So I downloaded the .jar, and then in the same directory made an HTML file into which I copy-pasted the <APPLET> tag from the original web page. I also downloaded any .js files linked to by that webpage just in case.

But when I try and run the applet by opening the HTML file in firefox, it throws null pointer exceptions. What's going on here, /prog/?

>>5
.j*? What, as in .j followed by anything?

Now that you mention it, the document Head does link to two JavaScript files with weird extensions:

"/java.js?8" and "/javagame/dust/dust.js?24"

Why, what are they?