DateTime JavaScript vs C#

Question

Regardless of many posts I've read the magic still in my code. I have DateTime value in db ('2011-03-30 00:00:00.000') that I retrieve for asp.net/mvc page where some javascript needs to read it and compare. The magic in the following:

<% 
DateTime unixTimeOffset = new DateTime(1970, 1, 1, 0, 0, 0, 0);
DateTime testDate = new DateTime(2011,03,30,0,0,0,0);
%>
<%= (testDate - unixTimeOffset).TotalMilliseconds %>
...

Last string of the code gives me this value: 1301443200000 When I try to read it in JavaScript I have:

val myDate = new Date(1301443200000);

And myDate is Tue Mar 29 2011 20:00:00 GMT-0400 (Eastern Daylight Time) {} But not a March 30th as it should be.

I understand it provides date referencing to local time, GMT-4 but what is the solution to get it independent? Any ideas? Thanks.

Answer 1

For C# Related Dates:

You may want to consider using DateTime.ToUniversalTime() and .UTCNow() , which will allow you to keep all days independent of time-zones.

 DateTime date = DateTime.UTCNow();

For Javascript-Related Dates:

Javascript features a UTC Method that should get you the Universal Time as well.

//Declaration
var date = new Date(Date.UTC(YYYY,MM,DD));

//Use
var newDate = date.toUTCString();

Hope this helps :)

Answer 2

Get the timezone offset in the client and add that to the value from the server. Like this:

var serverOffset = 1301443200000;
var localOffset = myDate.getTimezoneOffset() * 60 * 1000;
var myDate = new Date(serverOffset + localOffset);
console.log(myDate); // Wed Mar 30 2011 00:00:00

Please note that Tue Mar 29 2011 20:00:00 GMT-0400 (Eastern Daylight Time) is the same point in time as your original date in UTC. This method creates a new date that represents a new point in time . However, if you're just trying to display the same date value, then this method does the trick.

Alternatively, you can use Date 's UTC methods to print your original date in UTC:

function pad(num) {
    return ("0" + num).slice(-2);
}

function formatDate(d) {
    return [d.getUTCFullYear(), 
            pad(d.getUTCMonth() + 1), 
            pad(d.getUTCDate())].join("-") + "T" + 
           [pad(d.getUTCHours()), 
            pad(d.getUTCMinutes()), 
            pad(d.getUTCSeconds())].join(":") + "Z";
}

formatDate(new Date(1301443200000));

Output:

"2011-03-30T00:00:00Z"

Answer 3

Your code is correct. The myDate variable holds the correct date since Tue Mar 29 2011 20:00:00 GMT-0400 is the same point in time as Wed Mar 30 2011 00:00:00 GMT+0000 . My guess is that you see the former since that is your computers time zone. Use myDate.toUTCString() to see the date as UTC.