moment-msdate.js (original) (raw)
An OLE Automation date, or “MSDate” as we call it, is implemented as a floating-point number whose integral component is the number of days before or after midnight, 30 December 1899, and whose fractional component represents the time on that day divided by 24. For example, midnight, 31 December 1899 is represented by 1.0; 6 A.M., 1 January 1900 is represented by 2.25; midnight, 29 December 1899 is represented by -1.0; and 6 A.M., 29 December 1899 is represented by -1.25.
Read more about OLE Automation on MSDN (including DateTime.ToOADate and DateTime.FromOADate).
Some of Market Data APIs use MSDates in their response.