js.Script = weekDaysFrom

Number of Weekdays From a Target Date

To install this script, follow these simple steps:

1. Cut and paste this script into the HEAD of your document:

<SCRIPT LANGUAGE="JavaScript" TYPE="text/JavaScript">
  <!--

/* Written by: Mark Woodward (June, 2000)
     Woody's JavaScripts at: woody.cowpi.com/javascripts.html

The function weekDaysFrom is a WEEKDAY counter. Weekends are not included
     in the count. It calculates the number of weekdays from a given date,
     startDate, to another date, chkDate. The startDate is included in the
     count. A list of holidays or non-working weekdays can be created to
     subtract from the count.   */

// List any non-working weekdays here (DO NOT include any weekend dates)
  var dayOff = new Array();
  dayOff[0] = new myDate(1999, 12, 25);   // Old Xmas date for demo

function myDate(y, m, d) {

/* y: 4 digit year, m: month (range: 1-12), d: day (range: 1-?)
       If no parameters are passed, then current date is used.
       myDate object has two properties:
         jDate  - javascript Date object
         dayNum - adjusted javascript representation of day number
                  (counts milliseconds from 1970/1/1)   */

if (y != null) this.jDate = new Date(y, m-1, d);
      else this.jDate = new Date();
    this.dayNum = Math.floor(this.jDate.getTime() / 86400000);
    }

function weekDaysFrom(startDate, chkDate) {

/* startDate and chkDate are myDate objects.
       startDate MUST be a weekday! (Erroneous results for weekend dates.)
       chkDate can be ANY date after the startDate.  */

var dowC = chkDate.jDate.getDay();
    var dowS = startDate.jDate.getDay();
    var numDays = chkDate.dayNum - startDate.dayNum;
    var numWks = Math.floor((numDays + dowS - 1) / 7);
    var remainder = (dowC % 6);
    var wkDays = 5 * (numWks - 1) + remainder + 6 - dowS;
    if (remainder == 0) wkDays += 5;
    for (var i = 0; i < dayOff.length; i++)
      if ((chkDate.dayNum >= dayOff[i].dayNum) && (dayOff[i].dayNum > startDate.dayNum)) wkDays--;
    if (wkDays <= 0) wkDays--;
    return wkDays
    }

// -->
  </SCRIPT>

2. Cut and paste this into the BODY of your document: