if (document.images) {
    // preload the alternate images offscreen
   prodon = new Image();
   prodon.src = "images/prod-on.gif";
   buyon = new Image();
   buyon.src = "images/buy-on.gif";
   wholon = new Image();
   wholon.src = "images/whol-on.gif";
   recipeon = new Image();
   recipeon.src = "images/recipe-on.gif";
   repson = new Image();
   repson.src = "images/reps-on.gif";
   abouton = new Image();
   abouton.src = "images/about-on.gif";
   contacton = new Image();
   contacton.src = "images/contact-on.gif";
   prodoff = new Image();
   prodoff.src = "images/prod-off.gif";
   buyoff = new Image();
   buyoff.src = "images/buy-off.gif";
   wholoff = new Image();
   wholoff.src = "images/whol-off.gif";
   recipeoff = new Image();
   recipeoff.src = "images/recipe-off.gif";
   repsoff = new Image();
   repsoff.src = "images/reps-off.gif";
   aboutoff = new Image();
   aboutoff.src = "images/about-off.gif";
   contactoff = new Image();
   contactoff.src = "images/contact-off.gif";
}

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

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