Converting Excel Date Serial Number to Date using Javascript

Question

I have the following javascript code that convert date (string) to the Date Serial Number used in Microsoft Excel:

function JSDateToExcelDate(inDate) {      var returnDateTime = 25569.0 + ((inDate.getTime() - (inDate.getTimezoneOffset() * 60 * 1000)) / (1000 * 60 * 60 * 24));     return returnDateTime.toString().substr(0,5);  } 

So, how do I do the reverse? (Meaning that a Javascript code that convert the Date Serial Number used in Microsoft Excel to a date string?

Answer 1

Try this:

function ExcelDateToJSDate(serial) {    var utc_days  = Math.floor(serial - 25569);    var utc_value = utc_days * 86400;                                            var date_info = new Date(utc_value * 1000);     var fractional_day = serial - Math.floor(serial) + 0.0000001;     var total_seconds = Math.floor(86400 * fractional_day);     var seconds = total_seconds % 60;     total_seconds -= seconds;     var hours = Math.floor(total_seconds / (60 * 60));    var minutes = Math.floor(total_seconds / 60) % 60;     return new Date(date_info.getFullYear(), date_info.getMonth(), date_info.getDate(), hours, minutes, seconds); } 

Custom made for you :)

Answer 2

I made a one-liner for you:

function ExcelDateToJSDate(date) {   return new Date(Math.round((date - 25569)*86400*1000)); }