Test whether a Date instance is valid. A valid date returns a number for its timestamp, and NaN otherwise. NaN is never equal to itself.
Return a standard YYYY-MM-DD string for the Date instance.
The date in YYYY-MM-DD format
Return a standard H:M:S.Z string for the Date instance.
The time in H:M:S format
Test whether a Date instance is valid. A valid date returns a number for its timestamp, and NaN otherwise. NaN is never equal to itself.