// Firefox
var theday = new Date(2017, 2, 3, 0, 0, 0, 0);
// Date 2017-03-02T16:00:00.000Z
// 2 -> March, 0 based
// UTC Time: 03/02 16:00
// UTC+8 Time: 03/03 00:00
theday.getDate()
// 3
theday.getUTCDate()
// 2
new Date(2017, 2, 3, 8, 0, 0, 0);
// Date 2017-03-03T00:00:00.000Z
new Date(Date.UTC(2017, 2, 3, 8, 0, 0, 0));
// Date 2017-03-03T08:00:00.000Z