Problem with ASP and JavaScript

I am using JavaScript as the server-side scripting language for ASP. I am difficulties where on the server side I am comparing the value of a variable to be "" or "undefined".
var myFirst = Request.QueryString("Name");
<%
if(typeof(myFirst) != "undefined")
{}
%>
It is entering inside the if loop anyways, even if it is having no values in the query string.
I am being advised to use VBScript for server-side scripting rather than JavaScript?
Will it be more advantageous to do so?
Thanks in advance.

the literal string "undefined" != undefined
you can use undefined without the quotes as long as undefined is ....not defined
ie
var undefined //do not do this,defines undefined
On the server I would use vbscript and I really like jscript.I am going to use vbscript one more time then make the move to C#
Charlie