var ajax = new Array();
function getSubZoneList(sel) {
	var zona = sel.options[sel.selectedIndex].value;
	document.getElementById('subzona').options.length = 0;	// Empty city select box
	if(zona.length>0){
		var index = ajax.length;
		ajax[index] = new sack();
		ajax[index].requestFile = 'includes/get_subzona.php?zona='+zona;	// Specifying which file to get
		ajax[index].onCompletion = function(){ createSubZone(index) };	// Specify function that will be executed after file has been found
		ajax[index].runAJAX();		// Execute AJAX function
	}
}
function createSubZone(index) {
	var obj = document.getElementById('subzona');
	eval(ajax[index].response);	// Executing the response from Ajax as Javascript code	
}