if (document.images) {
    // preload the alternate images offscreen
   homeon = new Image();
   homeon.src = "images/home-on.gif";
   conston = new Image();
   conston.src = "images/const-on.gif";
   commenton = new Image();
   commenton.src = "images/comment-on.gif";
   legpropon = new Image();
   legpropon.src = "images/legprop-on.gif";
   suggon = new Image();
   suggon.src = "images/sugg-on.gif";
   wisdomon = new Image();
   wisdomon.src = "images/wisdom-on.gif";
   campaignon = new Image();
   campaignon.src = "images/campaign-on.gif";
   homeoff = new Image();
   homeoff.src = "images/home-off.gif";
   constoff = new Image();
   constoff.src = "images/const-off.gif";
   commentoff = new Image();
   commentoff.src = "images/comment-off.gif";
   legpropoff = new Image();
   legpropoff.src = "images/legprop-off.gif";
   suggoff = new Image();
   suggoff.src = "images/sugg-off.gif";
   wisdomoff = new Image();
   wisdomoff.src = "images/wisdom-off.gif";
   campaignoff = new Image();
   campaignoff.src = "images/campaign-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");
 }
}