Hi Javier,

This is the script we use on our holiday form in-house. You'll just need to change add a class called "sdate" to you start date field, a class called "edate" to your end date field and a "total" class to your total days field.

function sumtotal() {
        var s = 0;
      	var e = 0;
      	//Get dates from input and reformat, then create date var
        $('.sdate input').each(function () {
          	s1 = $(this).val().replace("-", " ");
          	s2 = s1.replace("-", " 20");
            s = new Date(s2);
        });
      	$('.edate input').each(function () {
          	e1 = $(this).val().replace("-", " ");
          	e2 = e1.replace("-", " 20");
            e = new Date(e2);
        });
      
      var one_day=1000*60*60*24;
      var startMillis = s.getTime();
      var endMillis = e.getTime();
      var totalDays = (endMillis - startMillis)/one_day;
      var weekend = 0;
      var days = 0;
      
      for (var i = startMillis; i < endMillis; i += one_day) {
        var currentDay = new Date(i);
        if (currentDay.getDay() == 5 || currentDay.getDay() == 6) {
          weekend++;
        }
      }
	  	days = (totalDays+1) - weekend;

              
      		//Output value in the total class box
            if (isNaN(days)) {
      			$('.total input').val('Select dates');
            } else {
            	$('.total input').val(days);
            }
      
      	if (e.getTime() < s.getTime()) {
        	$('.edate input').val($('.sdate input').val());
        	sumtotal();
      	}
}

$(document).ready(function () {
  
    $(".sdate input").on('blur change', sumtotal);
  	$(".edate input").on('blur change', sumtotal);

});

Also this only works if the dates are in dd-MMM-yyyy format.

I hope this helps! Dan