CFLib.org – Common Function Library Project

Description:
Returns the day of the week for a date in the Julian. If no date is provided, defaults to the current day. Verified to be accurate between 400 and 9999 AD.

Return Values:
Returns an integer between 1 and 7 representing the day of the week (1=Sunday).

Example:

<CFOUTPUT>
#DayofWeekAsString(JulianDayofWeek("2/1/445"))#
</CFOUTPUT>

Parameters:

Full UDF Source:

/**
 * Returns the day of the week for a date in the Julian calendar.
 * The original alogrithim for the calculation was found at: http://www.faqs.org/faqs/calendars/faq/part1/
 * 
 * @param fullDate      Date you want to return the Julian day of the week for. 
 * @return Returns an integer between 1 and 7 representing the day of the week (1=Sunday). 
 * @author Beau A.C. Harbin (bharbin@figleaf.com) 
 * @version 1.0, September 5, 2001 
 */
function JulianDayofWeek(){
        var date=iif(arraylen(arguments) gt 0,"arguments[1]", "Now()");
    var month = DatePart("m", date);
    var day = DatePart("d", date);
    var year = DatePart("yyyy", date);
    var a = 0;
    var y = 0;
    var m = 0;
    var dayOfWeek = 0;
    a = (14 - month) \ 12;
    y = year - a;
    m = month + 12*a - 2;
    // for Julian calendar:
    dayOfWeek = ((5 + day + y + y\4 + (31*m)\12) mod 7)+1;

    // for Gregorian calendar:
    if(arraylen(arguments) EQ 0){
        dayOfWeek = DayofWeek(date);
    }

    return dayOfWeek;
}