TEMA:

function ff_calcdaysbetween_init()
{

setInterval('calcdays()',500);

} // ff_QuickForm300860205_init


function calcdays(){
var one_day=1000*60*60*24;
var days='';
var weekendDays = 0;
sdate=ff_getElementByName('start').value;
edate=ff_getElementByName('end').value;

start=new Date(ff_getElementByName('start').value);
end=new Date(ff_getElementByName('end').value);

while (start<= end) {
  var dayy = start.getDay();
  if (dayy == 0) {
    weekendDays++;
  }
 start= new Date(+start+ one_day);
}

var rez=weekendDays*2;
sdate = new Date(Number(sdate.split("-")[2]), Number(sdate.split("-")[0])-1, sdate.split("-")[1],0,0,0,0).getTime();
edate = new Date(Number(edate.split("-")[2]), Number(edate.split("-")[0])-1, edate.split("-")[1],0,0,0,0).getTime();

if(edate<sdate){ff_getElementByName('amount_days').value="end date before start date";}

else{
  days=edate-sdate;
 
  day=days/one_day;
  
  ff_getElementByName('amount_days').value=day-rez;

}

}