//at least one bug caught, could be more...

//Amazing piece covering the IFC (and calendars in general), used by Eastman Kodac into the 80s:

//https://99percentinvisible.org/episode/the-calendar/

​

​

function convertToIFC(today) {

  //var today = new Date();

​

  var YR = today.getYear();

  if (YR < 2000) {

    YR += 1900;

  }

  var LY = false;

  if ((YR % 4 == 0 && YR % 100 != 0) || YR % 400 == 0) {

    LY = true;

  }

  var DT = today.getDate();

  var MO = today.getMonth();

  var MOsum = new Array(31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30);

  if (LY) {

    MOsum[1] = 29;

  }

  var DOY = DT;

  for (i = 0; i < MO; ++i) {

    DOY += MOsum[i];

  }

  var IFCday = new Array(

    "Saturday",

    "Sunday",

    "Monday",

    "Tuesday",

    "Wednesday",

    "Thursday",

    "Friday"

  );

  var IFCmo = new Array(

    "January",

    "February",

    "March",

    "April",

    "May",

    "June",

    "Sol",

    "July",

    "August",

    "September",

    "October",

    "November",

    "December"

  );

  var IFCdate;

​

  function IFCd(n) {

    var result = n % 28;

    if (result == 0) {

      result = 28;

    }

    return result;

  }

​

  if (LY && DOY > 169) {

    IFCdate =

      IFCday[(DOY - 1) % 7] +

      ", " +

      IFCmo[parseInt((DOY - 1 + 27) / 28) - 1] +

      " " +

      IFCd(DOY - 1) +

      ".";

  } else {

    IFCdate =

      IFCday[DOY % 7] +

      ", " +

      IFCmo[parseInt((DOY + 27) / 28) - 1] +

      " " +

      IFCd(DOY) +

      ".";

  }

  if (LY) {

    if (DOY == 366) {

      IFCdate = "December 29, Year-Day.";

    }

    if (DOY == 169) {

      IFCdate = "June 29, Leap Year Day.";

    }

  } else {

    if (DOY == 365) {

      IFCdate = "December 29, Year-Day.";

    }

  }

  return IFCdate;

}

​