if (document.images) {

            keuze1on = new Image(); 
            keuze1on.src = "mouseover/keuze1_over.gif";   
            keuze2on = new Image();
            keuze2on.src = "mouseover/keuze2_over.gif";
            keuze3on = new Image();
            keuze3on.src = "mouseover/keuze3_over.gif";
  
           
            keuze1off = new Image(); 
            keuze1off.src = "mouseover/keuze1.gif"; 
            keuze2off = new Image(); 
            keuze2off.src = "mouseover/keuze2.gif";
            keuze3off = new Image(); 
            keuze3off.src = "mouseover/keuze3.gif";
 
           
            keuze1ad = new Image();
            keuze1ad.src = "mouseover/keuze1_plaatje.jpg";
            keuze2ad = new Image();
            keuze2ad.src = "mouseover/keuze2_plaatje.jpg";
            keuze3ad = new Image();
            keuze3ad.src = "mouseover/keuze3_plaatje.jpg";

            neutraal = new Image();
            neutraal.src = "mouseover/plaatje_neutraal.gif";
        }
function imgOn(imgName) {
        if (document.images) {
            document[imgName].src = eval(imgName + "on").src;
            document["common"].src = eval(imgName + "ad").src;
        }
}

function imgOff(imgName) {
        if (document.images) {
            document[imgName].src = eval(imgName + "off").src;
            document["common"].src = neutraal.src;
        }
}