function validateForm(formName) {
	var fRef = eval("document.forms['" + formName + "']");
	if (fRef.email.value.indexOf("@") < 1) {
		alert("Please ensure email address is in the form 'you@isp.com', then try again.");
		return(false);
	}
}

function getVal(el) {
  return el[el.selectedIndex].value
}

function fill_nights(f) {
  var MINUTE = 60 * 1000;
  var HOUR = MINUTE * 60;
  var DAY = HOUR * 24;
  
  var f = document.forms[f];
  
  var ay=getVal(f.elements['Arrival-Year']);
  var am=getVal(f.elements['Arrival-Month']);
  var ad=getVal(f.elements['Arrival-Day']);
  var dy=getVal(f.elements['Departure-Year']);
  var dm=getVal(f.elements['Departure-Month']);
  var dd=getVal(f.elements['Departure-Day']);
  
  var from=new Date(ay,am-1,ad);
  var till=new Date(dy,dm-1,dd);
  
  var nights=Math.floor((till-from) / DAY);
//  var nights=(till-from) / DAY;
  
//  if(nights>0 && nights <30)
  if(ay!=0 && am!=0 && ad!=0 && dy!=0 && dm!=0 && dd!=0 && nights>0)
    f.elements['Numbers-Of-Nights'].value=nights;
  return true;
}