function check_date(y,m,d,dn,displayMessage){
var checkstr = "0123456789";
var Datevalue = "";
var DateTemp = "";
var seperator = ".";
var day;
var month;
var year;
var leap = 0;
var err = 0;
var i;
   err = 0;


   /* if year is entered as 2-digit / always assume 20xx */
   year = document.getElementById(y).value;
   /* Delete all chars except 0..9 */
	DateTemp="";
   for (i = 0; i < year.length; i++) {
	  if (checkstr.indexOf(year.substr(i,1)) >= 0) {
	     DateTemp = DateTemp + year.substr(i,1);
	  }
	}
	year=DateTemp;

   year = '20'+year;
   if (year == 20) {
      err = 20;
   }
   /* Validation of month*/
    month = document.getElementById(m).value;
   /* Delete all chars except 0..9 */
	DateTemp="";
   for (i = 0; i < month.length; i++) {
	  if (checkstr.indexOf(month.substr(i,1)) >= 0) {
	     DateTemp = DateTemp + month.substr(i,1);
	  }
	}
  if (DateTemp.length==1) {
  	DateTemp="0"+DateTemp;
	  }
	  month=DateTemp;
   if ((month < 1) || (month > 12)) {
      err = 21;
   }
   /* Validation of day*/
   day = document.getElementById(d).value;
   /* Delete all chars except 0..9 */
	DateTemp="";
   for (i = 0; i < day.length; i++) {
	  if (checkstr.indexOf(day.substr(i,1)) >= 0) {
	     DateTemp = DateTemp + day.substr(i,1);
	  }
	}
  if (DateTemp.length==1) {
  	DateTemp="0"+DateTemp;
	  }
	day=DateTemp;
   if (day < 1) {
     err = 22;
   }
   /* Validation leap-year / february / day */
   if ((year % 4 == 0) || (year % 100 == 0) || (year % 400 == 0)) {
      leap = 1;
   }
   if ((month == 2) && (leap == 1) && (day > 29)) {
      err = 23;
   }
   if ((month == 2) && (leap != 1) && (day > 28)) {
      err = 24;
   }
   /* Validation of other months */
   if ((day > 31) && ((month == "01") || (month == "03") || (month == "05") || (month == "07") || (month == "08") || (month == "10") || (month == "12"))) {
      err = 25;
   }
   if ((day > 30) && ((month == "04") || (month == "06") || (month == "09") || (month == "11"))) {
      err = 26;
   }
   /* if 00 ist entered, no error, deleting the entry */
   if ((day == 0) && (month == 0) && (year == 00)) {
      err = 0; day = ""; month = ""; year = ""; seperator = "";
   }
 
   if (err == 0) {
     return true;
   }
   /* Error-message if err != 0 */
   else {
	   		if (displayMessage==true){
        alert(dn+"Date is not a valid date!");
				document.getElementById(m).select();
				document.getElementById(m).focus();
	   		}
	  return false;
   }
}

function check_StartAndEndDate()

{
var err;
	err= check_date("sYear","sMonth","sDay","Start ",true);
	if (err==false){
		return false;
	}
	err= check_date("eYear","eMonth","eDay","End ",true);
	if (err==false){
		return false;
	}
	return true;
}