<script>

function workingDaysBetweenDates(startDate, endDate) {

    var millisecondsPerDay = 86400 * 1000; 

    startDate.setHours(0,0,0,1);  

    endDate.setHours(23,59,59,999);  

    var diff = endDate - startDate;     

    var days = Math.ceil(diff / millisecondsPerDay);

    // Subtract two weekend days for every week in between

    var weeks = Math.floor(days / 7);

    days = days - (weeks * 2);

​

    // Handle special cases

    var startDay = startDate.getDay();

    var endDay = endDate.getDay();

    // Remove weekend not previously removed.   

    if (startDay - endDay > 1)         

        days = days - 2;      

    // Remove start day if span starts on Sunday but ends before Saturday

    if (startDay === 0 && endDay != 6)

        days = days - 1 ; 

    // Remove end day if span ends on Saturday but starts after Sunday

    if (endDay === 6 && startDay !== 0)

        days = days - 1  ;

    return days;

}

​

var a = new Date(2014, 09, 16); 

var b = new Date(2014, 09, 22);

var t = workingDaysBetweenDates(a,b);

alert(t);

​

​