How to create an array at the root level in Captivate using javascript?

I'm trying to create an array using a javascript window in captivate like this:

var questionOrder[20];

questionOrder[1]=1;

questionOrder[2]=2;

etc;

The purpose is to have a dynamic question order for a second attempt at a quiz, so that it will only include questions that the user got wrong on their previous attempt. When the user gets a question wrong, I put that question in the next available slot of the array to form a new question order for second quiz attempt. I do this using the javascript action:

questionOrder[zCount] = window.cpAPIInterface.getVariableValue("cpInfoCurrentSlide");

zCount=zCount+1;

As the action for leaving each slide, I have the following javascript executing:

iCount = iCount+1

window.cpAPIInterface.setVariableValue("cpCmndGotoSlide",questionOrder[iCount]);

This works with literal values, or even just the iCount variable, in place of questionOrder[], but it seems the array is not accessible from all slides.

How do I create an array at the root level so that it is always accessible?

TIA!

gCemb