Wed Jan 09 19:02:43 PST 2019

Search engines need to see content in order to list pages in their
massive keyword-based indices
They also need to have access to a
Hundreds of thousands of sites make the critical mistake of hiding or
obsfucating their navigation in ways that search engines cannot
access, thus impacting their ability to get pages listed in the search
happen:
important pages on the site, the spider has no way to reach them (or
even know they exist) because no direct, crawlable links point to
those pages
As far as Google is concerned, they might as well not
in the first place

attribute applied to them

index the contents of the referenced page