MSIE 6.0 Does Not Support Protyping With Objects Created With Document.createElement.

MSIE 6.0 apparently does not support protyping with objects created
with document.createElement, while Firefox does.

I tested it by typing it into the adress bar, but it also appears to be
the case for code embedded in a HTML document. Here's a simple segment
of code to demonstrate the difference:

javascript: function myObj(){};myObj.prototype =
document.createElement('a'); var x = document.createElement('a'); var
y=new myObj(); var z= new Object(); alert(x.href) /*blank in both FF &
MSIE6 */; alert(y.href) /* blank in FF but 'undefined' in MSIE6 */;
alert(z.href) /* 'undefined' in both FF & MSIE6 */;

I wonder why that is (apart from the fact that MSIE implements JScript
and not javascript), and can anyone tell me which of both browsers is
complient with W3C standards?