Question

how to create ontology automatically for websites?

Answer 1

If I understand your question, it's not possible o automate this. Here's the wikipedia definition for ontology: he philosophical study of the nature of being, existence or reality as such, as well as the basic categories of being and their relations

What this means to me is the study of information architecture - the organization of knowledge. The sort of thing that a good technical writer does as a job. I cannot see this being automated for a generation or so. Could be wrong ;-)