What are these TABs called and how to code them in html?

Hi,
To understand this, please take a look at this google search:
https://www.google.com/search?q=book+plot+the+road

Basically, when we search things like: "book plot some book name"
then google search page shows a tabbed like structure on the top of the page, with tabs like, "summary", "overview", etc.

How do I make these tabs in html? Is it possible to make these without the use of any graphics?
Thanks