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Esri recommends that databases are in UTC time. And if I’ve got this right, unless you set a time zone in your layer, you are entering a date in a date field as UTC. Mostly this is fine.You understand that the date refers to Pacific time for instance. You understand the date comes back to you the same value you put into the field. The problem comes when the browser or iOS or whatever device automatically localizes on initialization of a Date object.

Problem: When ArcGIS Server returns a date, it sends milliseconds since epoch UTC (unix time). However, the Javascript Date object always creates a localized date when you use that to instantiate a Date object, e.g. Pacific Daylight Time, moving it back -7 hours. Thus, March 16 0:00am in the data becomes March 15 5:00pm — one day early. How do you get the actual time storedin the database?

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1 Answer

Quick and easy solution, keep everything in UTC. Use the javascript getUTC functions to return UTC time, which will remove the localization offset on the date. (Yes, you could break this out into templates and formats, but really, how many different date formats do you need for most apps?)

http://www.spatialexception.org/posts/arcgis-server-and-javascript-dates

function getUTCDateYYYYMMDD(milliSecUnix) {
var d, mm, dd;
if (milliSecUnix) {
    d = new Date(milliSecUnix);
    mm = d.getUTCMonth() + 1;
    dd = d.getUTCDate();
    return (d.getUTCFullYear() + "-" +
            ((mm < 10) ? "0" + mm : mm) + "-" +
            ((dd < 10) ? "0" + dd : dd));
}
else {
    return "";
}

}

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