How to separate header/footer/carousell & other parts of website?

I want to separate out header/footer/sidebar/carousel of homepage of any of the website.

Example if I enter google.com or alibaba.com or flipkart.com

I can retrieve that homepage via PHP CURL. (some of them are encoded which we can't)

But question is how to identify that? Each platform is using different programming language.

Is they any API available free/paid in market? Is it possible?