How to use php and javascript to create an ecomerce site?

Question

Ecomerce Site

Answer 1

Not possible to answer so briefly. It may take hours.

Answer 2

You write php files which javascript calls. The php is on the web host server side.

Your question would take a lot of effort to answer.

You can always use a pre-made CART such as opencart or Magento and use php and javascript to customize it.

Making one from scratch is basically pointless and time consuming.