function chkwettbewerb(f){

	if(f.vorname.value==''){
		alert('Please give your first name.');
		f.vorname.focus();
		return (false);
		}

	if(f.nachname.value==''){
		alert('Please give your last name.');
		f.nachname.focus();
		return (false);
		}

	if(f.strasse.value==''){
		alert('Please give your street address.');
		f.strasse.focus();
		return (false);
		}

	if(f.ort.value==''){
		alert('Please give your city/town.');
		f.ort.focus();
		return (false);
		}

	if(f.plz.value==''){
		alert('Please give your postel / zip code.');
		f.plz.focus();
		return (false);
		}

	if(f.land.value==''){
		alert('Please give your country.');
		f.land.focus();
		return (false);
		}

	if(f.gjahr.selectedIndex==0){
		alert('Please give your birthday.');
		f.gjahr.focus();
		return (false);
		}

	if(f.gmonat.selectedIndex==0){
		alert('Please give your birthday.');
		f.gmonat.focus();
		return (false);
		}

	if(document.getElementById('gtagval').value==''){
		alert('Please give your birthday.');
		f.gjahr.focus();
		return (false);
		}

	if(f.telefon1.value==''){
		alert('Please give your phone number.');
		f.telefon1.focus();
		return (false);
		}

	if(f.email.value==''){
		alert('Please give your email address.');
		f.email.focus();
		return (false);
		}

	if(!isEmail(f.email.value)){
		alert('Please give a valid email address.');
		f.email.focus();
		return (false);
		}

	if(f.website.value==''){
		alert('Please give the link to your youtube video.');
		f.website.focus();
		return (false);
		}

	if(!confirm('Send form?')){return (false);}
	}

function chk28() {

var stdmonate='<select name="gtag" id="gtag" onchange="chtag()"><option value=""></option> <option value="1">1</option> <option value="2">2</option> <option value="3">3</option> <option value="4">4</option> <option value="5">5</option> <option value="6">6</option> <option value="7">7</option> <option value="8">8</option> <option value="9">9</option> <option value="10">10</option> <option value="11">11</option> <option value="12">12</option> <option value="13">13</option> <option value="14">14</option> <option value="15">15</option> <option value="16">16</option> <option value="17">17</option> <option value="18">18</option> <option value="19">19</option> <option value="20">20</option> <option value="21">21</option> <option value="22">22</option> <option value="23">23</option> <option value="24">24</option> <option value="25">25</option> <option value="26">26</option> <option value="27">27</option> <option value="28">28</option> ';
	if(document.wettbewerb.gmonat.selectedIndex==4 || document.wettbewerb.gmonat.selectedIndex==6 || document.wettbewerb.gmonat.selectedIndex==9 || document.wettbewerb.gmonat.selectedIndex==11) {
		document.getElementById('gmonatsval').innerHTML=stdmonate+'<option value="29">29</option> <option value="30">30</option> </select>';
		}
	else if (document.wettbewerb.gmonat.selectedIndex==2){
			if (schaltjahr(document.wettbewerb.gjahr[document.wettbewerb.gjahr.selectedIndex].value)){
				document.getElementById('gmonatsval').innerHTML=stdmonate+'<option value="29">29</option>  </select>';
				}
			else {
				document.getElementById('gmonatsval').innerHTML=stdmonate+'  </select>';
				}

		}
	else {
		document.getElementById('gmonatsval').innerHTML=stdmonate+'<option value="29">29</option> <option value="30">30</option> <option value="31">31</option> </select>';
		}
	
	}
	
function chtag(){
	document.wettbewerb.gtagval.value=document.getElementById('gtag').selectedIndex;
	}	

function schaltjahr(yr) {
if (((yr % 4 == 0) && yr % 100 != 0) || yr % 400 == 0)
   return true;
else
   return false;
}

function isEmail(s)
{
 var a = false;
 var res = false;
 if(typeof(RegExp) == 'function')
 {
  var b = new RegExp('abc');
  if(b.test('abc') == true){a = true;}
  }

 if(a == true)
 {
  reg = new RegExp('([\\w-\\.]+)@((\\[[0-9]{1,3}\\.[0-9]{1,3}\\.[0-9]{1,3}\\.)|(([\\w-]+\\.)+))([a-zA-Z]{2,4}|[0-9]{1,5})');
  res = (reg.test(s));
 }
 else
 {
  res = (s.search('@') >= 1 &&
         s.lastIndexOf('.') > s.search('@') &&
         s.lastIndexOf('.') >= s.length-5)
 }
 return(res);
}