C# jscript ?

Factual Questions
1

I’m working on my first deveopement in .NET and C#. It’s going to be web based.

I have WebForm1.aspx with HTML and JavaScript in it. A forms mousedown event launches a jscipt function that picks up the mouse X and Y position.

function mouseXY() {
mouseX=event.clientX + document.body.scrollLeft
mouseY=event.clientY + document.body.scrollLeft
}

How do I now call a class in WebForm1.aspx.cs, and pass the mouseX and Y values to it?

Thanks.