Not all the time you got pr3 if you launched incomplete site. The reason why it got pr3 is you promoted your site well and got more backlinks.
Actually this thread is really old. it's 50 days old! i had also a site which i worked for about a month, and it ranks high for several keywords to Google even though the site is under construction.
I am agree mate, thats its not in our control. But this links are really harmful for Search Engine Rank. Even if this kind of incoming links are more then you might get ban. This prove that my point is True.
i think using java script for site navigation is no problem. i use it for my new site and got PR3 from ZERO.
Well, You guys are discussing lot's of think but I don't think we need do this confuse??????????????????? your simple answer is here:- What Google Not Like: Black Hat SEO What Google Like: white Hat SEO