function getnumdays(indate,outdate) {

    var Nindate=indate.split("-")
    var Noutdate=outdate.split("-")
	
    Noutdate[1]=Noutdate[1]-1
	Nindate[1]=Nindate[1]-1

    var difference = Date.UTC(y2k(Noutdate[2]),Noutdate[1],Noutdate[0],0,0,0) -
                     Date.UTC(y2k(Nindate[2]),Nindate[1],Nindate[0],0,0,0);
    return difference/(1000*60*60*24);
}
function y2k(number) { 
return (number < 1000) ? number + 1900 : number; 
}

function checkstay(){
if((document.submitter.Arrival.value!="") && (document.submitter.Departure.value!="")){
inday=document.submitter.Arrival.value
outday=document.submitter.Departure.value
numbdays=getnumdays(inday,outday)
nights=eval(numbdays)
document.submitter.Duration.value=(nights + " Nights")
}
}