Mac is a great platform for your javascript, and for web development, particularly if you like forefox! ... IMO, your decision was lacking proper input!
The OS on the box is the same on my G5 desktop...
The mini is a G4, so why don't you look on eBay, or somewhere and buy a used one for a couple of hundred... then plug and play!
I will, thanks for the input. Java not javascript! I have my pride ya know.