Silverlight video player xap or js

I'm writing Silverlight video player and I sear开发者_JAVA技巧ch for inpiration so i have found JW Player.

But as I know Silverlight apps are inside .xap files and JW Player uses js script to implement SL logic.

Could you explain me how it works and why .js not .xap?

Thanks in advance.

That player was designed to work with Silverlight 1.0 or 1.1. If you check out the links to the Silverlight SDK from their page it links to SL v1 SDK.

I didn't start using SL till 2 but from my understanding SL 1 had a much heavier integration with JavaScript than 2 and beyond do. I doubt that the JW Player would work with current versions of Silverlight.