What is ASP.NET SPA?

I've recently spent time developing web applications with ASP.NET MVC 4, and recently enough, Microsoft published the first beta version of the MVC 4 framework to the web. In addition to enhancements and tunings to the regular MVC engine, the beta release contains additional new features like ASP.NET SPA, or Single-Page Applications.

What is the idea behind such single-page applications? Shortly put, the idea is to create modern web applications with more usage of JavaScript, instead of traditional page-oriented applications where the user moves from page to page to access different content. In respect, SPA applications are akin to many Silverlight applications in the sense that the user only sees a single "page".

In SPA applications, you can utilize any JavaScript engine you prefer, however, out of the box there's support for jQuery, Knockout, History and library called Upshot. Of these, Upshot is something I've not used previously, but looking forward to learning about it, too.

For more information about single-page applications, see here.