function upper(el) {
  el.value = el.value.toUpperCase()
}

function lower(el) {
  el.value = el.value.toLowerCase()
}	

function checkvroegvalues(){ //test invoer boeking form 1
	var msg='';
	var error=0;
//alert('CHECK')
  for(var x=0;x< document.f.elements.length;x++){
  	if( (document.f.elements[x].getAttribute("required") != null) && (document.f.elements[x].getAttribute("required")=='Y') && (document.f.elements[x].value.length == 0)){
	  	msg += 'Veld ' + document.f.elements[x].name + ' is niet ingevuld!\n';
	    error++;
	  }
	}
  var goodEmail = document.f.email.value.match(/\b(^(\S+@).+((\.com)|(\.net)|(\.edu)|(\.mil)|(\.gov)|(\.org)|(\..{2,2}))$)\b/gi);
  if(!goodEmail){
		error+=1;
		msg += 'E-mail adres is ongeldig\n'
	}
	var ok = true;
	var telchk  = new Array('1','2','3','4','5','6','7','8','9','0','/','.','-',' ','+','(',')')
  for (var i = 0; i < document.f.telefoon.value.length; i++) {
    var chr = document.f.telefoon.value.charAt(i);
    var found = false;
    for (var j = 0; j < telchk.length; j++) {
      if (chr == telchk[j]) {
			  found = true
		 	}
    }
    if ((!found) || (document.f.telefoon.value.length < 6)) {
	    ok = false
	  }
  }
  if (!ok) {
		error++;
		msg += 'Telefoonnummer is ongeldig\n';
	}
	if (error>0) {
		alert(msg);
		return false;
	}
	return true;	
}