if (document.images)
   {
     pic1on= new Image(86,16);
     pic1on.src="images/overknop-verbalight.gif";  
     pic2on= new Image(155,16);
     pic2on.src="images/overknop-verlichtingsonderh.gif"; 
     pic3on= new Image(115,16);
     pic3on.src="images/overknop-noodverlichting.gif"; 
     pic4on= new Image(99,16);
     pic4on.src="images/overknop-groothandel.gif"; 
 	 pic5on= new Image(133,16);
     pic5on.src="images/overknop-ultrasoon.gif";
     pic6on= new Image(77,16);
     pic6on.src="images/overknop-specials.gif";
     pic9on= new Image(140,16);
     pic9on.src="images/overknop-energiebesparing.gif";
     pic12on= new Image(140,16);
     pic12on.src="images/overknop-contact.gif";
     

     pic1off= new Image(86,16);
     pic1off.src="images/knop-verbalight.gif";
     pic2off= new Image(155,16);
     pic2off.src="images/knop-verlichtingsonderhoud.gif";
     pic3off= new Image(115,16);
     pic3off.src="images/knop-noodverlichting.gif";
     pic4off= new Image(99,16);
     pic4off.src="images/knop-groothandel.gif";
     pic5off= new Image(133,16);
     pic5off.src="images/knop-ultrasoon.gif";
     pic6off= new Image(77,16);
     pic6off.src="images/knop-specials.gif";
     pic9off= new Image(140,16);
     pic9off.src="images/knop-energiebesparing.gif";
     pic12off= new Image(140,16);
     pic12off.src="images/knop-contact.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;
    }
 }