When a posted link shows up as a blank page, an easy fix is to copy/paste to your desired browser. So try to copy/paste that into an internet browser. As for an exact rainbow bbcode, I've never heard of one, but I'm sure that the link is something close to what you're looking for.
@ww Yeah, but if the link has an ampersand in it (usually does), you'll need to put it into bitly or tinyurl and get a small URL. Then you can put it in the Code: [url=example] [/url] hope my bbcodes work