function obtenerPoblaciones(ctrl, modulo, def, sLocalidad){

	var numargs = obtenerPoblaciones.arguments.length;
	var idProvincia = ctrl.options[ctrl.selectedIndex].value;
	var obj = document.getElementById('sLocalidad');
	obj.options.length = 0;

	if(idProvincia > 0){
	
		var req = new XMLHttpRequest();
	
		if(req){
			req.onreadystatechange = function(){
				if (req.readyState == 4 && (req.status == 200 || req.status == 304)){
					try {
						if(req.responseText.length > 0){
							eval(req.responseText);
						}
					} catch (ex){
						alert("Error AJAX: " + ex);
					}
				}
			}
		}
		
		var requestStr = 'includes_web/db_poblacionesAJAX.asp?modulo=' + modulo + '&idProvincia=' + idProvincia;
		if(numargs > 3) requestStr += '&sLocalidad=' + sLocalidad;
		req.open('GET', requestStr);
		req.send(null);
		
	} else {
		
		obj.options[obj.options.length] = new Option(def,'0');
		
	}
}