if (document.images)
   {
     pic1on= new Image(199,28);
     pic1on.src="images/overknop-start.gif";  
     pic2on= new Image(199,28);
     pic2on.src="images/overknop-kleinverpakkingen.gif"; 
     pic3on= new Image(199,28);
     pic3on.src="images/overknop-cosmeticapotten.gif"; 
     pic4on= new Image(199,28);
     pic4on.src="images/overknop-grootverpakkingen.gif"; 
	 pic5on= new Image(199,28);
     pic5on.src="images/overknop-tapkranen.gif"; 
	 pic6on= new Image(199,28);
     pic6on.src="images/overknop-metaalverpakkingen.gif"; 
	 pic7on= new Image(199,28);
     pic7on.src="images/overknop-sluitingen.gif";
	 pic8on= new Image(199,28);
     pic8on.src="images/overknop-doseerpompen.gif";
	 pic9on= new Image(199,28);
     pic9on.src="images/overknop-fabrieken.gif";
	 pic10on= new Image(199,28);
     pic10on.src="images/overknop-fotoboek.gif";
	 pic11on= new Image(199,28);
     pic11on.src="images/overknop-contact.gif";
	 pic12on= new Image(199,28);
     pic12on.src="images/over-vlag-nl.gif";
	 pic13on= new Image(199,28);
     pic13on.src="images/over-vlag-uk.gif";

     pic1off= new Image(199,28);
     pic1off.src="images/knop-start.gif";  
     pic2off= new Image(199,28);
     pic2off.src="images/knop-kleinverpakkingen.gif"; 
     pic3off= new Image(199,28);
     pic3off.src="images/knop-cosmeticapotten.gif"; 
     pic4off= new Image(199,28);
     pic4off.src="images/knop-grootverpakkingen.gif"; 
	 pic5off= new Image(199,28);
     pic5off.src="images/knop-tapkranen.gif"; 
	 pic6off= new Image(199,28);
     pic6off.src="images/knop-metaalverpakkingen.gif"; 
	 pic7off= new Image(199,28);
     pic7off.src="images/knop-sluitingen.gif";
	 pic8off= new Image(199,28);
     pic8off.src="images/knop-doseerpompen.gif";
	 pic9off= new Image(199,28);
     pic9off.src="images/knop-fabrieken.gif";
	 pic10off= new Image(199,28);
     pic10off.src="images/knop-fotoboek.gif";
	 pic11off= new Image(199,28);
     pic11off.src="images/knop-contact.gif";
	 pic12off= new Image(199,28);
     pic12off.src="images/vlag-nl.gif";
	 pic13off= new Image(199,28);
     pic13off.src="images/vlag-uk.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;
    }
 }