I have a large PR8 frames based site (I know, I know!) that used to have excellent rankings in Google with approximately 100 000 pages indexed. Since March the number of hits from Googlebot has fallen dramatically, and over time all my ordinary HTML pages are disappearing from Google. I have a noframe backdoor linking to all content pages. When an ordinary user hits the content frame of a page, a Javascript will open the navigation frames. Could it be that Googlebot now reads the Javascript and then can't find its way back to the content? Anyone else experienced something similar?