We’ve mostly finished our journey through the client-side portion of a web application. Although I haven’t stated it explicitly, when I refer to the client-side portion of a web app, I’m talking about the part of the program that runs in your web browser. The other side of the story is the server-side part of the application, which runs and stores information outside of your web browser, usually on a remote computer.
This chapter is not about the server-side part of a web application, but it is about a collection of technologies that allow the client and server to more easily exchange information. I like to think of this set of technologies as the bridge between the client and the server.