How to correctly check the text according to Zipf's law?

Question

Search Engine Optimization

Such a question is a text according to the Zipf law on one of the sites gives 87%, and if you check the same test but already on the site page, then 50%. So what is the correct way to check the text separately or the entire page? If the whole page is the right solution, then how to get rid of everything superfluous, I mean the menu and products on the page.

Answer 1

Use Dom Path search.
Example: output.jsbin.com/uhude3/4