var browserOK = false;
  var pics;





  browserOK = true;
  pics = new Array();









var objCount = 0; 

function preload(name, first, second) {  

  

  if (browserOK) {     
    pics[objCount] = new Array(3);
    pics[objCount][0] = new Image();
    pics[objCount][0].src = first;
    pics[objCount][1] = new Image();
    pics[objCount][1].src = second;
    pics[objCount][2] = name;
    objCount++;
  }
}

function on(name){
  if (browserOK) {
     for (i = 0; i < objCount; i++) {
      if (document.images[pics[i][2]] != null)
        if (name != pics[i][2]) { 
          // set back all other pictures
          document.images[pics[i][2]].src = pics[i][0].src;
        } else {
          
           document.images[pics[i][2]].src = pics[i][1].src;
        }
    }
  }
}

function off(){
  if (browserOK) {
     for (i = 0; i < objCount; i++) {
      if (document.images[pics[i][2]] != null) 
        document.images[pics[i][2]].src = pics[i][0].src;
    }
  }
}



preload("link1", "image/offers.jpg", "image/offersneg.jpg");
preload("link2", "image/links.jpg", "image/linksneg.jpg");
preload("link3", "image/about.jpg", "image/aboutneg.jpg");