function setBackground()
{
   var image=new Image();
   image.onload=function() {
      document.body.style.backgroundImage="url("+image.src+")"
   };
   image.onerror=function() {
      document.body.style.backgroundImage="url(../figuren/achtergronddefault.jpg)";
   };
   
   var bestand = location.pathname.substring(location.pathname.lastIndexOf('/')+1, location.pathname.length)
   if (bestand.match('proces%20en%20techniek'))
      image.src="../figuren/achtergrondproces"+screen.width+screen.height+".jpg"
   else if (bestand.match('wetgeving'))
      image.src="../figuren/achtergrondwetgeving"+screen.width+screen.height+".jpg"
   else
      image.src="../figuren/achtergrond"+screen.width+screen.height+".jpg"
   
   document.body.style.backgroundColor="#bb4";
   document.body.style.backgroundRepeat="no-repeat";
}
         
function showPopup(id) {
   document.getElementById(id).style.visibility='visible';
}

function hidePopup(id){
   document.getElementById(id).style.visibility='hidden';
}