How do I call a C# function in javascript?

Perhaps you'd like to elaborate on what you are doing so we have more to go on.

-Peter
compiledthoughts.com

The specific of in what environment you are running the JavaScript and where the C# function is located would be of assistance.

In a general case you can often (provided you are running JavaScript in a Microsoft environment, e.g. IE) create instances of COM objects (using the new ActiveXObject() command), and you can also expose your C# applications to COM (using COM interop).

http://www.webreference.com/js/column55/activex.html

/- Sam Judson : Wrox Technical Editor -/

I answered this one before:
http://p2p.wrox.com/topic.asp?TOPIC_ID=73936

If you look at his other posts, you find he is trying to pan an image and then capture the panned-to position. He wants then send that position back to the server so that he can get a zoomed-into image at that same pan position.

It's actually all pretty straightforward, but he is trying to learn three different technologies all at once, it seems, and gets the "how to" confused.