function changecolor(item, kleur) {document.getElementById(item).style.background=kleur}
function interchangedisplay (item1, item2) {document.getElementById(item1).style.display='none';document.getElementById(item2).style.display=''}
function show(ident,idshow,idhide) {
document.getElementById(ident).style.display='block';
document.getElementById(idshow).style.display='none';
document.getElementById(idhide).style.display='block';
}
function hide(ident,idshow,idhide) {
document.getElementById(ident).style.display='none';
document.getElementById(idshow).style.display='block';
document.getElementById(idhide).style.display='none';
}