if (document.images)
   {
     pic1on= new Image(19,125);
     pic1on.src="images/overknop-bedrijf.gif";  
     pic2on= new Image(18,125);
     pic2on.src="images/overknop-assortiment.gif"; 
     pic3on= new Image(19,125);
     pic3on.src="images/overknop-acties.gif"; 
     pic4on= new Image(19,125);
     pic4on.src="images/overknop-mappenmaken.gif"; 
     pic5on= new Image(18,125);
     pic5on.src="images/overknop-vacatures.gif";
     pic6on= new Image(18,125);
     pic6on.src="images/overknop-voorwaarden.gif"; 
     pic7on= new Image(20,125);
     pic7on.src="images/overknop-contact.gif"; 

     pic1off= new Image(19,125);
     pic1off.src="images/knop-bedrijf.gif";
     pic2off= new Image(18,125);
     pic2off.src="images/knop-assortiment.gif";
     pic3off= new Image(19,125);
     pic3off.src="images/knop-acties.gif";
     pic4off= new Image(19,125);
     pic4off.src="images/knop-mappenmaken.gif";
     pic5off= new Image(18,125);
     pic5off.src="images/knop-vacatures.gif";
     pic6off= new Image(18,125);
     pic6off.src="images/knop-voorwaarden.gif";
     pic7off= new Image(20,125);
     pic7off.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;
    }
 }
 
  
  
 function showSubmenu() {
 	var submenu = document.getElementById('submenu');
 	submenu.style.visibility = 'visible';
 }
 
  
 function hideSubmenu() {
 	var submenu = document.getElementById('submenu');
 	submenu.style.visibility = 'hidden';
 }