Why does JavaScript show me one day before my set date?

Question

I'm trying see dates based off of some json data I have.

My code is:

var date = new Date(json.events[i].event.first_date);
alert(date);

Now, that json.events[i].event.first_date just returns the date in the format of yyyy-mm-dd.

I noticed, however that when I do the alert(date);, I'm shown the day before the date that the actual data says.

For example, json.events[0].event.first_date gives the date 2015-06-02 but the alert shows June 1, 2015.

I am getting my json from a url based somewhere in Germany and I am in the US. Could the date be messed up because of timezones?

where is the javascript code running? In Germany or in the US? — Cacho Santa, Sep 03 '15 at 21:35
see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Date/getTimezoneOffset — biziclop, Sep 03 '15 at 21:42
After concatenating ' 00:00:00 GMT' to my Date string ('Thu Oct 01 2015 00:00:00 GMT') I got the correct date. (Since I don't need the time anyway). new Date('Thu Oct 01 2015 00:00:00 GMT') — Ricardo Corrêa de Souza, Oct 08 '15 at 04:10
just concat the time 'T00:00' , eg: var date = new Date(json.events[i].event.first_date +'T00:00' ); — nativelectronic, Jul 18 '22 at 20:07

score 5 · Accepted Answer · answered Sep 03 '15 at 21:38

When you create date from string without timezone you get a date + timezone correction – if you're in USA then you have something like GMT-7 and you get the second of June minus 7 hours – the previous day. Try splitting your date and use new Date(2015, 7, 1) constructor and you'll get date you're expecting. String parse reference docs -https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Global_Objects/Date/parse

Why does JavaScript show me one day before my set date?

1 Answers1