How to change html using chrome extension?

Question

JavaScript

I am interested in the api method or what to enter in the manifest, is XMLHttpRequest () necessary, is it possible without it?

Answer 1

Content Script: https://developer.chrome.com/extensions/content_scripts

Answer 2

mayorovp : do you know how to determine the end of downloading a file from a site? and if this happens, automatically do something with the page?

habrdima : downloading exactly the file? Not pages?
Then check out https://developer.chrome.com/extensions/downloads.