if (document.images)
   {
     pic1on= new Image(53,30);
     pic1on.src="images/overknop-home.gif";  
     pic2on= new Image(45,30);
     pic2on.src="images/overknop-ipod.gif"; 
     pic4on= new Image(57,30);
     pic4on.src="images/overknop-top-40.gif"; 
     pic5on= new Image(91,30);
     pic5on.src="images/overknop-top-albums.gif"; 
     pic6on= new Image(90,30);
     pic6on.src="images/overknop-downloads.gif"; 
     pic7on= new Image(114,30);
     pic7on.src="images/overknop-hoe.gif";
     pic8on= new Image(52,30);
     pic8on.src="images/overknop-links.gif"; 


     pic1off= new Image(53,30);
     pic1off.src="images/knop-home.gif";
     pic2off= new Image(45,30);
     pic2off.src="images/knop-ipod.gif";
     pic4off= new Image(57,30);
     pic4off.src="images/knop-top-40.gif";
     pic5off= new Image(91,30);
     pic5off.src="images/knop-top-albums.gif";
     pic6off= new Image(90,30);
     pic6off.src="images/knop-downloads.gif";
     pic7off= new Image(114,30);
     pic7off.src="images/knop-hoe.gif";
     pic8off= new Image(52,30);
     pic8off.src="images/knop-links.gif";
   }

function lightup(imgName)
 {
   if (document.images)
    {
      imgOn=eval(imgName + "on.src");
      document[imgName].src= imgOn;
    }
 }

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