As you can see in the source code, Andre implemented to ECMAScript 5.1 Date.prototype.toJSON method. toJSON just calls the toISOString() function to retreive the value. /* Serializes a <code>Date</code> object as a JSON-String * as specified in ECMAScript5, chapter 15.9.5.44
5.1 Spec: > 15.9.5.43 Date.prototype.toISOString ( ) > This function returns a String value represent the instance in time > represented by this Date object. The format > of the String is the Date Time string format defined in 15.9.1.15. All fields > are present in the String. The time > zone is always UTC, denoted by the suffix Z. var d = new Date(); d.toJSON() returns "2012-03-22T08:36:05.088Z" d.toISOString() returns "2012-03-22T08:36:05.088Z" d.toDateString() returns "Thu Mar 22 2012" d.toLocaleString() returns "Thu Mar 22 2012 09:36:05 GMT+0100 (CET)" d.getTimezoneOffset() returns -60 You could use the getTimezoneOffset() function to do the calculation of your local time, though. - Raju
