Representation State Transfer (REST)

How did modern web applications come to be? How do we take advantage of the asynchronous nature of the internet? What do we mean by a REST API?
And why can we not hit the back button when using SIS?
Representation State Transfer (REST) is an architectural design pattern that emphasizes statelessness on web servers to allow for better application scaling, multiple clients from the same user, and overall better management of user state. Most MVC frameworks are built with REST in mind, including Django.