function woordenboek(woord_id) {
	var page = "woordenboek.php?woord_id=" + woord_id;
	windowprops = "height=250,width=450,location=no,"
	+ "scrollbars=yes,menubars=no,toolbars=no,resizable=no";
	window.open(page, "woordenboek_popup", windowprops);
  }