How to check for silverlight browser capability - preferably server side?

Thanks for your answer.

I tried checking Silverlight.available, but I get a JavaScript error - says that "Silverlight" is not defined, however, the rest of the silverlight specific code on the page works fine.

Have you ever come across this?

Thanks for all your comments guys.

I've ended up using the client side check, and then using Ajax to get the data back to my database.

I've been logging the info for a couple of days now. So far only 29% of page views have reported that Silverlight is installed. Info on the web suggested that it was 50% back during the Beijing Olympics (where it was used for the media player on the official site).

It's a shame for two reasons. 1 because silverlight is a brilliant technology, and integrates so well with .NET, and 2 because I spent ages slaving over this control I made ! :(

Thanks