function setSubSelectOptions(){
	var selectedIndex = document.getElementById('mainSelect').selectedIndex;
	var varSel = document.getElementById('subSelect');
	
	var optionsArray = new Array(2);
	optionsArray[1] = new Array('Stad in bedrijf', 'Business in Facillities');
	optionsArray[2] = new Array('Personeel en salaris vakdagen 2004', 'Integrale Veiligheid 2005');
	optionsArray[4] = new Array('ATPS internetsite', 'Google', 'Ilse');	

	varSel.options.length = 0;
	if (optionsArray[selectedIndex] != null){
		varSel.options[0] = new Option('Maak uw keuze', 'Geen keuze gemaakt');
		
		for (i = 0; i < optionsArray[selectedIndex].length; i++){
			varSel.options[varSel.options.length] = new Option(optionsArray[selectedIndex][i], optionsArray[selectedIndex][i]);
		}

		varSel.options[varSel.options.length] = new Option('Overig', 'Overig');

		document.getElementById('subSelect').disabled = false;
		document.getElementById('tbOther').readOnly = true;
		document.getElementById('tbOther').value = 'Overig';
	}
	else{
		document.getElementById('subSelect').disabled = true;
		toggleBoxReadOnly('mainSelect')
	}
}

function toggleBoxReadOnly(source){
	var varSel = document.getElementById(source);
	if (varSel.options[varSel.selectedIndex].innerHTML == 'Overig'){
		document.getElementById('tbOther').readOnly = false;
	}
	else{
		document.getElementById('tbOther').readOnly = true;
	}
	document.getElementById('tbOther').value = 'Overig';	
}