if (document.images) {

  var homeOff = new Image(); // for the inactive image
  homeOff.src = "/images/navhomeoff.gif";
  var homeOn = new Image(); // for the active image
  homeOn.src = "/images/navhomeon.gif";
  
  var tipsOff = new Image(); // for the inactive image
  tipsOff.src = "/images/navtipsoff.gif";
  var tipsOn = new Image(); // for the active image
  tipsOn.src = "/images/navtipson.gif";

  var aboutOff = new Image(); // for the inactive image
  aboutOff.src = "/images/navaboutoff.gif";
  var aboutOn = new Image(); // for the active image
  aboutOn.src = "/images/navabouton.gif";

  var shopOff = new Image(); // for the inactive image
  shopOff.src = "/images/navshopoff.gif";
  var shopOn = new Image(); // for the active image
  shopOn.src = "/images/navshopon.gif";

  var portfolioOff = new Image(); // for the inactive image
  portfolioOff.src = "/images/navportfoliooff.gif";
  var portfolioOn = new Image(); // for the active image
  portfolioOn.src = "/images/navportfolioon.gif";
  
  var contactOff = new Image(); // for the inactive image
  contactOff.src = "/images/navcontactoff.gif";
  var contactOn = new Image(); // for the active image
  contactOn.src = "/images/navcontacton.gif";

  
}

function rollOff(imgName) {
 if (document.images) {
    document[imgName].src = eval(imgName + "Off.src");

}
}	

function rollOn(imgName) {
 if (document.images){
	document[imgName].src = eval(imgName + "On.src");
	
}
}

<script language="Javascript1.2">

// (C) 2003 CodeLifter.com
// Source: CodeLifter.com
// Do not remove this header

// Set the message for the alert box
am = "This function is disabled!";

// do not edit below this line
// ===========================
bV  = parseInt(navigator.appVersion)
bNS = navigator.appName=="Netscape"
bIE = navigator.appName=="Microsoft Internet Explorer"

function nrc(e) {
   if (bNS && e.which > 1){
      alert(am)
      return false
   } else if (bIE && (event.button >1)) {
     alert(am)
     return false;
   }
}

document.onmousedown = nrc;
if (document.layers) window.captureEvents(Event.MOUSEDOWN);
if (bNS && bV<5) window.onmousedown = nrc;

</script>