A HTML shopping cart is essentially a shopping cart that is made in the programming language of HTML and is built to be placed on a website so that users can purchase products online.
HTML shopping cart software is more advanced than simple buy now buttons that exist through various payment providers like PayPal, as it allows users to add multiple products to a cart then process them all with a single payment transaction.
Thus added features need to be included so that a user can continue to browse the online store while still keeping the previous selected products in their cart.
There are many different software solutions that are pre-made html shopping carts, so there is no need to go and design your own these days.
There are simple plugins for blogging platforms such as the ecommerce plugins to WordPress, there are open source complete ecommerce solutions such as Magento and OS Commerce plus there are hosted solutions such as Shopify, Big Commerce and Volusion.
Depending on your level of skill, size of store and budget will depnd on which kind of solution you go for.
WordPress is easy to install and cheap to use, but has limited options. Magento and OS Commerce are complex to install and configure but have great flexibility and are free, while the hosted solutions such as Volusion, Shopify and Big Commerce are all easy to use and flexible but are expensive as come with a monthly fee.
You need to figure out your positron is and decide which one is going to be the best solution for your business as each business and online store is different and has different needs. If you are only selling a small, single product you don’t need a big robust system. And if you are massive online store, you don’t want a small system that cant scale.