browserOK = true;
pics = new Array();

if (browserOK) {
var nm=navigator.appName+navigator.appVersion;
browserOK=((nm.indexOf("Netscape3.")>-1||nm.indexOf("Netscape4.")>-1||nm.indexOf("Explorer4.")>-1)?1:0);
}

var objCount = 0; // number of (changing) images on web-page

function preload(name, first, second) {

  // preload images and place them in an array

  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
          if (pics[i][0].complete)
            document.images[pics[i][2]].src = pics[i][0].src;
        } else {
            // show the second image because cursor moves across this image
            if (pics[i][1].complete)
              document.images[pics[i][2]].src = pics[i][1].src;
        }
    }
  }
}

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

preload("nav1", "images/nav_2.jpg", "images/nav_on_2.jpg");
preload("nav2", "images/nav_3.jpg", "images/nav_on_3.jpg");
preload("nav3", "images/nav_4.jpg", "images/nav_on_4.jpg");
preload("nav4", "images/nav_5.jpg", "images/nav_on_5.jpg");
preload("nav5", "images/nav_6.jpg", "images/nav_on_6.jpg");
preload("nav6", "images/nav_7.jpg", "images/nav_on_7.jpg");