I know that using a javascript menu should generally be avoided, and the use of pure CSS menus is preferred.
However, in some cases I consider using js menus to list pages that are less important, seo wise (such as "contact us", "about us", "my account" (for users that logged in) etc.).

My question is:
Are js menus harmful to page SEO on their own? or their harm is only the lack of positive SEO that exists in pure CSS menus?
In other words, when Google robot encounters a js based menu, does it ignore it and continue to scan the page, or does it "think": "hmm, there are hidden links here, this site uses black hat SEO!"