Please help with this Javascript

I am having trouble getting this script to reset. This script aloows the user to select a region and in turn, the countries below shift in accordance with the region they choose. The problem occurs when the make a selection and go to a new page... if they try to go back to the script, the region resets but the countries do not! I need to figure out how to get the countries to go back to their default. Can anyone help?

<!--
var regionsArray = new Array(7);
regionsArray[0] = new Array("Botswana","Ethiopa","Kenya","Madagascar","Mali","Morocco","Namibia","South Africa","Tanzania","Uganda","Zambia","Zimbabwe");
regionsArray[1] = new Array("Argentina","Belize","Bolivia","Brazil","Chile","Costa Rica","Galapagos","Panama","Peru");
regionsArray[2] = new Array("Bhutan","Burma","Cambodia","China","India","Ladakh","Laos","Multi-Country","Nepal","Thailand","Tibet","Vietnam");
regionsArray[3] = new Array("Greece","Italy","Turkey");
regionsArray[4] = new Array("Egypt","Iran","Israel","Jordan","Lebanon","Oman","Syria");
regionsArray[5] = new Array("Australia","Hawaii","Indonesia","New Zealand","Samoa");
regionsArray[6] = new Array("Antarctic","Arctic")
function updateCountries(n) {
var arr = regionsArray[n];
var current = document.forms[0].countries.options.length;
for (var j=current;j>0;j--) document.forms[0].countries.options[j] = null;
for (var i=0;i<arr.length;i++) document.forms[0].countries.options[document.forms[0].countries.options.length] = new Option(arr[i],arr[i]);
}
-->

What's the default state for the countries list?

I want region to default to Africa and the countries to default to the corresponding african countries. Currently, the countries remain on the last region selected so if the user selects americas for example, then goes back, the region will be on africa but the countries will be the american countries.

how about putting

onLoad("updateCountries(0);")

in the body tag?

That didn't help. Any more clues?