function hideDateFields() {
	el_ids = [['year', 0], ['month', 1], ['day', 2]];
	visibility = 'visible';
	for (i in el_ids) {
		getElement('id_from_' + el_ids[i][0]).style.visibility = visibility;
		getElement('id_to_'   + el_ids[i][0]).style.visibility = visibility;
		if (getElement('id_time_step_' + el_ids[i][1]).checked) visibility = 'hidden';
	} 
}

function possibleDisableZoneSelect() {
	zone_select = getElement('id_zone')
	zone_label_td = getElement('zone_label_th')
	if (getElement('id_stat_type').value in statsWithZonesJS) {
		zone_select.disabled = false;
		zone_select.className = '';
		zone_label_td.className = ''
	} else {
		zone_select.disabled = true;
		zone_select.className = 'disabled_item';
		zone_label_td.className = 'disabled_item'
	}
}

function myLoadFunction() {
	if (getElement('stats_form')) {
	   	// Start functions after load
	    hideDateFields();
	    possibleDisableZoneSelect();
	    
	    // Connect function with objects
	    for (i = 0; i < 3; i++) connect(getElement('id_time_step_' + i), 'onclick', hideDateFields);
	    connect(getElement('id_stat_type'), 'onchange', possibleDisableZoneSelect);
	}
	
};
MochiKit.DOM.addLoadEvent(myLoadFunction);