function triggerError(t) {
  alert('Het veld \''+t+'\' is niet (correct) ingevuld');
}

function chk_text(frm,v,t) {
  f = frm.elements;
  if (f[v].value != '') result=true; else result=false;
  if (result==false) triggerError(t);
  return result;
  } 

function chk_radio(frm,v,t) {
  f = frm.elements;
  result = false;
  for (i=0; i<f.length; i++) {
    if (f[i].name==v) {
      result = result | f[i].checked;
    }
  }
  return result;
} 

function chk_select(frm,v,t) {
  f = frm.elements;
  sel = f[v];
  return (sel.selectedIndex > 0);
} 

function chk_checkbox(v,t) {
  f = frm.elements;
  result = false;
  for (i=0; i<f.length; i++)
    if (f[i].name==v)
      result = result | f[i].checked;
  return result;
} 


function editfURL() {
			
	if(document.getElementById('edit_fURL').checked) {
		document.getElementById('fURL').readOnly = false;
	} else {
		document.getElementById('fURL').readOnly = true;
	}
	
}