function geboortedag() {
	month = $('maand').selectedIndex;
	month = $('maand').options[month].value;
	day = $('dag').selectedIndex;
	day = $('dag').options[day].value;
	year = $('jaar').value;
	
	var oyear=year
	
	var dob = " "+ year +", "+month + ",  "+day;
	var thenx = new Date(dob);
	
	var year=thenx.getYear();
	if (year<100) year="19" + thenx.getYear();
	else year=thenx.getYear();
	
	if (year > 1969) wyear=year;
	else {
	if (oyear<1900) {
	if (oyear>1800) {
	wrelyear= (eval(oyear)-1801)%(28);
	wyear = wrelyear+1981;
	}
	else wyear = 1970 
	}
	else
	if (oyear>1900) {wrelyear= (eval(oyear)-1901)%(28); 
	wyear= wrelyear+1985
	}
	else 
	if (oyear==1900) {wyear= 1990;
	   }              
	}
	var dob = " "+ wyear +", "+month + ",  "+day;
	var thenx = new Date(dob);
	
	var theday = thenx.getDay()+1;
	var date=thenx.getDate();
	
	var weekday = new Array(6);
	weekday[1]="Zondag";
	weekday[2]="Maandag";
	weekday[3]="Dinsdag";
	weekday[4]="Woensdag";
	weekday[5]="Donderdag";
	weekday[6]="Vrijdag";
	weekday[7]="Zaterdag";
	
	if ( month == "January" ) month = "Januari";
	if ( month == "February" ) month = "Februari";
	if ( month == "March" ) month = "Maart";
	if ( month == "April" ) month = "April";
	if ( month == "May" ) month = "Mei";
	if ( month == "June" ) month = "Juni";
	if ( month == "July" ) month = "Juli";
	if ( month == "August" ) month = "Augustus";
	if ( month == "September" ) month = "September";
	if ( month == "October" ) month = "Oktober";
	if ( month == "November" ) month = "November";
	if ( month == "December" ) month = "December";

	
	if (day != date)
	$('geboortedag').innerHTML = "<br/><br/>Deze datum klopt niet<br/><br/><br/>";
	

	else {
	dayborn = weekday[theday];
	dob = "<b>" + dayborn + "</b><br/> " + date + " " + month + " " + oyear + "";
	$('geboortedag').innerHTML = "<br/><br/>U bent geboren op<br/> " + dob + "<br/><br/>";
   }
}