Develop Reference

Why does Javascript show me the wrong date?

Consider the following date object which is created in JavaScript.
var date = new Date("2017-09-07T16:46:06.000Z");
This date object should be equivalent to Sep 7 2017 4:46:06 PM
However, in the browser console, when I type the following:
console.log(date);
The following is returned:
Fri Sep 08 2017 02:46:06 GMT+1000 (E. Australia Standard Time)
The time is wrong. (It actually is today's date, but the time is completely wrong).
Key points of confusion:
My computer timezone is set to GMT+1000 (Australia/Brisbane)
When I created the date object, I did not specify the timezone, therefore it should conform to my systems timezone
When I log the date object to the console, it is still using GMT+1000 (Australia/Brisbane) but the date is different

When you created the date, you did specify a timezone. That Z at the end means Zulu or Greenwich Mean Time. Your computer is 10 hours off from GMT, so it adjusts to your local timezone for display.
If you want the date to be in your local time zone, remove the Z

var date = new Date("2017-09-07T16:46:06.000Z");
So it looks like the Z at the end of your date string is meant to represent UTC or Zulu time
var date = new Date("2017-09-07T16:46:06.000");
should be the correct solution

Javascript date object automatically add one day when creating from date string

In my javascript i want to convert date from date string.
i have string like
date = "Thu Sep 03 2015 19:30:00 GMT+0000"
Now i convert string using Date object.
var d = new Date(date);
But this gives me,
Fri Sep 04 2015 01:00:00 GMT+0530 (IST)
It automatically add one day into day. What is wrong?

It automatically add one day into day. What is wrong?
Nothing. The time you input is 19:30 GMT and the timezone on the device you're using is set to GMT+0530. Add 5 hours 30 minutes to 7:30pm and you get 01:00am the following day.
You should not use the Date constructor to parse strings, as it is inconsistent across browsers and until recently, entirely implementation dependent. Manually parse strings, or use a Date library.

How to keep the Date as it is without being converted into local time zone?

I am having issue with the localtime zone things in javascript. If I got a string value from the server is "2014-02-03T00:00:00.000Z", once I pass it into Date object new Date('2014-02-03T00:00:00.000Z'), the new date object will be in localtime zone ex. Sun Feb 02 2014 18:00:00 GMT-0600 (CST). How to keep the value as 'Mon Feb 03 2014 00:00:00' ? I see a lot of people is using moment.js for dealing date, but I don't find any help with this issue.
Thanks

You can use getUTCDate() method. It will return you correct date.
http://jsbin.com/zizukapuba/1/edit?output
It will convert the date into required format with reference to system local timezone.
NOTE: If you use, the getISOString() method, then it will again make the changes with reference to your local time, that is, GMT -6.00.

The Date object stores your date as "2014-02-03T00:00:00.000Z".
When you display your Date object, the toString() function is used to get a string to display the date. toString() displays the date using the local time zone. Try using the toISOString() function or toUTCDateString().

Javascript date formatting - one hour out due to daylight saving

So now, its 9:23am. I have a UTC date string that represents the current date, that looks like this "2012-07-17T09:23:27.75"
I want that in a date object, so I can display a nicely formatted date, so I:
var myDate = new Date("2012-07-17T09:23:27.75")
// Gives --> Tue Jul 17 2012 10:23:27 GMT+0100 (GMT Daylight Time)
So because of daylight saving time I'm getting an hour-out issue. I can see that myDate.getTimezoneOffset() gives me -60, what's the standard / best practice way to get my date to actually reflect the current correct time? Have I just entered javascript date hell?

Try momentjs.com. I really found it handy for such things.
var myDate = moment("2012-07-17T09:23:27.75");
Gives you a date instance in your timezone (that basically configured on your computer). Moreover momentjs has nice human friendly formattings like "a couple of seconds ago", "a month ago",...
Dates are really a hell in JS (but not only in JS). The best thing you can do is to always only transport in UTC between browser <-> server. Then on the server convert it to what time format you like, you obviously only have to be consistent. That way I managed to handle date-times properly.

Try removing the 'T'
I was debugging some date time format issue in chrome when I found out that in console
new Date('2016-04-16T15:15:00') returns Sat Apr 16 2016 16:15:00 GMT+0100 (GMT Daylight Time)
while
new Date('2016-04-16 15:15:00') returns Sat Apr 16 2016 15:15:00 GMT+0100 (GMT Daylight Time)

Convert date/time in GMT to EST in Javascript

In Javascript, how can I convert date/time in GMT to EST irrespective of user settings?

var tmpDate = New Date("enter any valid Date format here")
The javascript Date() function will automatically convert it to your local time.
Example:
var tmpDate = new Date("Fri Jul 21 02:00:00 GMT 2012");
alert(tmpDate);
//Result: Fri Jul 20 22:00:00 EDT 2012
Try some different values at jsfiddle: http://jsfiddle.net/R3huD/

i was surprise to find the simplest solution.
If you have date in GMT, and when you create date in browser it always create in that time zone.
Simplest way is create date object with GMT itself and then do below
starTime.setHours(starTime.getHours()+(starTime.getTimezoneOffset()/60));
That's it. Even if you have date of future after day light saving like after November then also it will also work.

See here:
https://web.archive.org/web/1/http://articles.techrepublic%2ecom%2ecom/5100-10878_11-6016329.html
all you have to do is get the time in miliseconds and then add the offset in milliseconds and then shift back to a date time object