DATETOSECONDS - convert date string to integer.

DateToSeconds ([S]) returns I

converts the string S into an integer giving the number of seconds since "1 Jan 1970 00:00 GMT". The argument S is a string consisting of a date and time. If you want midnight on a particular day, specify "00:00". If you omit the argument, IF uses the current time as an argument. If the argument contains a date but no time, the function uses noon on that date.