if (document.images) {
  image1On = new Image();
  image1Off = new Image();
  image1On.src = "images/middle_tab_danglersOn.gif";
  image1Off.src = "images/middle_tab_danglersOff.gif";
  image2On = new Image();
  image2Off = new Image();
  image2On.src = "images/middle_tab_gardenOn.gif";
  image2Off.src = "images/middle_tab_gardenOff.gif";
  image3On = new Image();
  image3Off = new Image();
  image3On.src = "images/middle_tab_objetOn.gif";
  image3Off.src = "images/middle_tab_objetOff.gif";
  image4On = new Image();
  image4Off = new Image();
  image4On.src = "images/middle_tab_seafoodOn.gif";
  image4Off.src = "images/middle_tab_seafoodOff.gif";
  image5On = new Image();
  image5Off = new Image();
  image5On.src = "images/top_tab_homeOn.gif";
  image5Off.src = "images/top_tab_homeOff.gif";
  image6On = new Image();
  image6Off = new Image();
  image6On.src = "images/top_tab_aboutusOn.gif";
  image6Off.src = "images/top_tab_aboutusOff.gif";
  image7On = new Image();
  image7Off = new Image();
  image7On.src = "images/top_tab_linksOn.gif";
  image7Off.src = "images/top_tab_linksOff.gif";
  image8On = new Image();
  image8Off = new Image();
  image8On.src = "images/top_tab_contactusOn.gif";
  image8Off.src = "images/top_tab_contactusOff.gif";
  image9On = new Image();
  image9Off = new Image();
  image9On.src = "images/top_tab_postOn.gif";
  image9Off.src = "images/top_tab_postOff.gif";
  
}

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

function imgOff(imageName){
    if (document.images){
      document[imageName].src = eval(imageName+"Off.src");
    }
  }