Silverlight is a cut down version of the Windows Presentation Foundation, and was formally known as Windows Presentation Foundation Everywhere (WPF/E). This cut down version includes the base class library and WPF libraries that allow .NET developers to program .NET code that can be hosted in any web browser and on any platform – Windows, Linux and Apple Macintosh.

Silverlight 1.0 was released some time ago and concentrated on media, i.e Video and Music players. There was nothing of any real interest for 50 hour a week coders. This however, has changed with a Silverlight beta 2.0, that is available which incorporates a whole host of controls. In traditional ASP.NET applications, AJAX is the most recent technology to be used to enhance user interaction with a web-page. AJAX is client focused, which means that as one browses through a web-site, one doesn’t get the page flicker and reload each time you interact with a server control or web-page. Traditionally you send a HTTPGET request to the server and it responds. AJAX uses JavaScript heavily to interact in the browser on the client machine. AJAX is essentially a hack, but it works. It gets rid of the annoying flickering, and the whole experience with the web-browser is ostensibly mellifluous.

With these two client focused technologies, Microsoft have had to shift focus to the client machine again. I started out in ASP.NET and recently returned to client development, and can truthfully say that Microsoft have put enormous resources into their web stack. Which is server based. Independent ISV’s have supplied the client stack rather well, so for a while, things trundled along nicely.

Then along came Silverlight. The principal requirement for Silverlight (like Adobe flash) is that end user download a plug-in for their browser. Microsoft have had to do some really deep thinking into what they put in and leave out. The total size at the moment is less than 5MB, so space and optimised code became a priority by default. They needed to provide a plug-in that was as full featured, but as small as possible.

One of the undoubted results of this ‘trimming-down’ exercise is the procurement of the client profile. This is such a big feature in the forthcoming .NET 3.5 service pack, and it’s all been brought about thinking as small as possible and getting the biggest result, insofar as ease of deployment.