// 参考 https://www.sejuku.net/blog/30171
var _time = new Date();
- var _log_date = _time.getFullYear() + "/" + _time.getMonth() + "/" + _time.getDate() + " " + _time.getHours() + ":" + _time.getMinutes() + ":" + _time.getSeconds();
+ var _log_date = _time.getFullYear() + "/" + Number(_time.getMonth() + 1) + "/" + _time.getDate() + " " + _time.getHours() + ":" + _time.getMinutes() + ":" + _time.getSeconds();
// console.log (_log_date);
_log_box.value = "\n" + "[" + _log_date + "]" + _msg +_log_box.value;