function countSelected(select, maxNumber, messagetext) { 
	var selectedOptions=[];
	qua=0;
	for(var i=0; i<select.options.length; i++) {
		if(select.options[i].selected) {
			qua++;
			if(selectedOptions.length>maxNumber) {
				alert(messagetext+maxNumber);
				select.options[i].selected=false;
				qua--;
			} else {
				selectedOptions[qua]=i;
			}
		}
	} 
}

function submit_form(thisform, thisvalue, thismissing) {
	if(thisvalue=='') {
		alert('Eerst dient u '+thismissing+' in te vullen');
		return;
	}
	thisform.submit();
}

function check_enter_general(form) {
	if(self.event.keyCode==13) {
		form.submit();
	}
}

function valid_email(email) {
	test=new String(email);
	if(test.indexOf('@', 0)==-1) {
		return false;
	}
	if(test.indexOf('.', 0)==-1) {
		return false;
	} else {
		var ind=test.indexOf('.', 0);
	}
	while(ind!=-1) {
		var indl=ind+1;
		ind=test.indexOf('.', indl);
	}
	if((indl-2)<=test.indexOf('@', 0)) {
		return false;
	}
	return true;
}