What is used to make this site?

hi all,

i’m making a website for a band, and i really like the way www.thejulianatheory.com is done - that it’s not a fully flash site, but it appears to be html that loads into the one page. What language is used to do this? It’s weird because when i try to view the source code there’s pretty much nothing there, but if i select a bit of text and view IT’S code, it appears to be plain hmtl.

is it somehow loaded dynamically in? i like it because it doesn’t need to reload unnecessary bits so it looks nicer (than having the momentary white page as new stuff loads) and it also means the mp3 player doesn’t keep reloading (any other way to do this?).