function checkNumber(evt) {
  var theEvent = evt || window.event;
  var key = theEvent.keyCode || theEvent.which;
  key = String.fromCharCode( key );
  var regex = /[0-9]|\./;
  if( !regex.test(key) ) {
    theEvent.returnValue = false;
    if(theEvent.preventDefault)
      theEvent.preventDefault();
    alert("Enkel getallen toegelaten.");
  }
}

function showhidefield(name, count)
{
  //OLD: WORKS FOR FIREFOX/CHORME ONLY
  /*
  var items = document.getElementsByName("hideablearea")
  if(document.getElementById("partner").checked)
  {
    for(var i = 0; i < items.length; i++){
      items[i].style.visibility = "visible";
    }
  }
  else
  {
    for(var i = 0; i < items.length; i++){
      items[i].style.visibility = "hidden";
    }
  }
  */
  //Check if the checkbox is checked
  var checkbox = document.getElementById("partner");
  
  var showpartner = "hide";
  if(checkbox.checked == true){
    showpartner = "show";
  }
  for(i = 1; i <= count; i++)
  {
    var elem = document.getElementById(name + i);
    if(elem)
    {
      /*
      if(elem.className == "" || elem.className == "show")
      {
        elem.className = 'hide';
      }
      else{
        elem.className = 'show';
      }
      */
      elem.className = showpartner;
    }
  }
}

function popup(mylink, windowname)
{
if (! window.focus)return true;
var href;
if (typeof(mylink) == 'string')
   href=mylink;
else
   href=mylink.href;
window.open(href, 'details', 'width=600,height=650,scrollbars=yes,resizable');
return false;
}