Comparison Between Silverlight 1.0 and 2.0

Silverlight 1.0 is a cross-platforms and cross-browsers plugin to display Web pages holding XAML code.
Silverlight 2.0 (formerly 1.1) is an interface to .NET. It also works with most browsers, but it requires the .NET platform under Windows or compatible under other OS. This enables it to use languages other than JavaScript. Actually it has a virtual machine such as Java.

Features
Silverlight 1.0
Silverlight 2.0
AJAX
Yes
Yes
Cross browsers
Yes
Yes
Cross platforms (Windows, Mac, Linux).
Yes
Yes
Integration into HTML
Yes
Yes
Using DOM
Yes
Yes
HTTP Functions
Yes
Yes
JavaScript language
Yes
Yes
C Sharp Language
-
Yes
Other .NET languages
-
Yes
2D Graphic
Yes
Yes
JPG et PNG Images
Yes
Yes
High definition video
Yes
Yes
Audio/Video (VC-1, WMV, WMA, MP3)
Yes
Yes
ASP.NET Controls (as asp:xaml)
Yes
Yes
XAML Parser
Yes
Yes
Framework with collections and genericity
-
Yes
Improved security
-
Yes
Isolated backup
-
Yes
JSON Web services
-
Yes
LINQ
-
Yes
Read write XML on the server
-
Yes
Download size
2 MB
4 MB

It is not said if the two solutions will coexist, or if the latter will have to replace the first. Version 1.0 is a subset of 2.0, which offers greater portability through the virtual machine and should replace the first version.

More details on Microsoft's site in the article Silverlight Overview.

Silverlight 1.1 has been renamed 2.0.

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