function date_diff(date_form, date_to) {
	today = new Date();
	c_date = today.getFullYear() + "/" + (today.getMonth() + 1) + "/" + today.getDate();
	if (date_form=="now") {
		obj_date_from = new Date(c_date);
	} else {
		obj_date_from = new Date(date_from);
	}
	if (date_to=="now") {
		obj_date_to = new Date(c_date);
	} else {
		obj_date_to = new Date(date_to);
	}
	diff = obj_date_to - obj_date_from;
	diff = diff/86400000;
	return diff;
}