A Single Page Application (SPA) is a different way of building HTML 5 applications from traditional Web page development. Instead of spreading the functionality of your Web applications across a collection of separate Web pages with hyperlinks between them, you instead define a single root page that the user lands on and never leaves as long as they are working with your application. You define client-side logic that switches out the data and chunks of content within that page to allow the user to navigate from logical screen to logical screen without ever leaving the page. This means that the user never sees a full page refresh while using your application. They see portions of the screen change based on their interaction, and those changes can be done in a more fluid way with transitions to enhance the user experience. You can also support using the application while offline by storing data client-side, based on some of the newer APIs of HTML 5. Taking this approach makes an SPA feel very much like a desktop application to the end user.