Question

How can I call a Asp.Net function within parameter the result of a javascript function ?

Something like that :

var a = <%= MyFunction(getJs()) %>;

I know that something like that work :

var a = <%= MyFunction("test") %>;

Answer 1

You can’t mix server and client code. <%= %> is executed on the server, and the javascript is executed on the client.

You should probably investigate another approach. For example, depending on what your MyFunction() method does, consider porting it to your javascript.