[variable1] Has No Properties

I am getting a Javascript error from Firefox 1.0.5 when I try to reference a
table within a window that has just been opened and written to. I get the
Javascript error "cartTable has no properties" where cartTable is the
variable I assigned the table reference to.

cartTable=winDVDCart.document.getElementById("cartTable")

Previous to this, I have just opened a new window, used the document.write
method to write some HTML into it, and then used the document.close method.
At that point I call a new function to add some extra things into the new
window and this is the first statement that gets run. It seems as if the
table isn't quite finished loading when I try to reference it and that is
causing problems. I am not getting any errors in IE6 and it is working just
fine. I figured that maybe I could implement a loop to just wait until the
table is fully loaded but that will just loop infinitely for some odd
reason.

while (!winDVDCart.document.getElementById("cartTable")) {}

This code just loops infinitely, but if I just put an alert within the {}
for the while loop, it shows the alert once, I click ok and everything works
great after that. Could anyone point me in the right direction on this?