Chapter 10. Geolocation, Offline Web Apps, and Web Storage

Much of what is loosely considered to be a part of “HTML5” isn’t, strictly speaking, HTML at all—it’s a set of additional APIs that provide a wide variety of tools to make our websites even better. We introduced the concept of an API way back in Chapter 1, but here’s a quick refresher: an API is an interface for programs. So, rather than a visual interface where a user clicks on a button to make something happen, an API gives your code a virtual “button” to press, in the form of a method it calls that gives it access to a set of functionality. In this chapter, we’ll walk you through a few of the most useful of these APIs, as well as give you a brief overview of the others, and point you in the right direction should you want to learn more.

With these APIs, we can find a visitor’s current location, make our website available offline as well as perform faster online, and store information about the state of our web application so that when a user returns to our site, they can pick up where they left off.