function prefSelect() {
	id = document.selectForm.prefId.selectedIndex;
	document.selectForm.cityId.length = 1;
	for( i=0; i<medwebPrefs[id].length; i++ ) {
		document.selectForm.cityId.options[i+1] = new Option( medwebPrefs[id][i][1], medwebPrefs[id][i][0] );
	}
}

function mapView() {
	var f = document.selectForm;
	step1 = f.prefId.options[ f.prefId.selectedIndex ].value;
	step2 = f.cityId.options[ f.cityId.selectedIndex ].value;
	step3 = f.serviceId.options[ f.serviceId.selectedIndex ].value;
	
	if( step1 > 0 ) {
	location.href = "/map/" + step1 + "/" + step2 + "/" + step3 + ".html";
	} else if( step3 > 0 ) {
		location.href = "/service/" + step3 + "/" + step1 + "/" + step2 + ".html";
	}
}
function serviceView() {
	var f = document.selectForm;
	step1 = f.serviceId.options[ f.serviceId.selectedIndex ].value;
	step2 = f.prefId.options[ f.prefId.selectedIndex ].value;
	step3 = f.cityId.options[ f.cityId.selectedIndex ].value;
	
	if( step1 > 0 ) {
	location.href = "/service/" + step1 + "/" + step2 + "/" + step3 + ".html";
	} else if( step2 > 0 ) {
		location.href = "/map/" + step2 + "/" + step3 + "/" + step1 + ".html";
	}
}