function openen(pagina,breedte,hoogte) {
url = pagina;
window_name = "";
properties = "toolbar=no,location=0,directories=no,status=no,menubar=0,scrollbars=no,resizable=1,copyhistory=0,width=" +
breedte + ",height=" + hoogte + ",left=0,top=0";
instructions = window.open(url, window_name, properties); }

function openen2(pagina,breedte,hoogte) {
url = pagina;
window_name = "";
properties = "toolbar=no,location=0,directories=no,status=no,menubar=0,scrollbars=yes,resizable=1,copyhistory=0,width=" +
breedte + ",height=" + hoogte + ",left=0,top=0";
instructions = window.open(url, window_name, properties); }

function bepaalQI(){
			document.getElementById('qindex').value=Math.round((document.getElementById('weight').value*10000)/(document.getElementById('length').value*document.getElementById('length').value));
}