Subj : undefined variables
To   : netscape.public.mozilla.jseng
From : Stuart
Date : Tue Aug 24 2004 08:39 pm

Hi,

I am a little confused as to the use of undefined in javascript and Rhino.

I think my fundamental problem is that I do not understand the purpose of
having both an Undefined and Null type/value in ECMAScript.

If I was creating a variable:

	String name = null;
	ScriptableObject.defineProperty(myScope, "userName", name,
ScriptableObject.READONLY);

Is it possible to set the 'value' of userName to undefined? -OR- Would you
just not call defineProperty for a variable that you wanted to be undefined?

Also can you programatically test to see if the value of a variable is
undefined?  I noticed that the getProperty can return Scriptable.NOT_FOUND -
is this equivalent to undefined?

Thanks in advance,

Stuart Broad

.