Apache is a free and open-source cross-platform web server software.
Websites that have a shopping cart or checkout page, either using a known ecommerce platform or a custom solution.
Modernizr is a JavaScript library that detects the features available in a user's browser.
PayPal is an online payments system that supports online money transfers and serves as an electronic alternative to traditional paper methods like checks and money orders.
Shopware is an enterprise-level ecommerce platform.
A modest JavaScript framework for the HTML you already have.