Write VB code in file . JS

Question

You can write Vb code inside a file that looks like . js?

For example: arquivo teste.js

var testeEvento = function () {
    <%=MsgBox("teste")%>;
    };

I tried this way it didn’t work it returns me that:

Uncaught SyntaxError: Unexpected token <

And when executing:

Uncaught ReferenceError: testeEvento is not defined
    at <anonymous>:1:1