Is it necessary to make a html file in a folder for every single product page(for each product) or can i do this with JS. If got 1000 products that would be a lot of files.
If you know some pages where this Problem is shown(thought), pls send me the link.
you can use some e-commerces frameworks like Woocommerce, Magento or Prestashop.
you can also make your code with some server-side langague like Node.JS or PHP, with these languages is just make a template of product page and add variables with product data.
Tutorials:
Frameworks: