Are php, html & css enough to create a big multifunctional online platform?

Question

I am not from computer field but I am interested in these stuff too. My main aim is to create an awesome e-com portal & not to learn each and every concept of programming (i.e. irrelvant stuff for my purpose). I know html, css, little bit js & learning php for backend work. I need someone to clear my doubts. I am unable to find over internet my answers.

Answer 1

JS or jQuery is necessary to control user-interface and sending data to php (jQuery - ajax - json)

You need a database to store all data

Answer 2

Can I use php instead of js/jquery to send/receive data..?

Answer 3

I am not sure, maybe it is possible..
https://www.ostraining.com/blog/coding/retrieve-html-form-data-with-php/

..but you can't control/edit UI without javascript functions.