var browser = navigator.userAgent.substring(0,7);
var version = parseInt(navigator.userAgent.substring(8,9));
  
function loadImages(prefix) {
  if ((browser == "Mozilla") && (version >= 3)) {
    ln0 = new Image();
    ln0.src = prefix+"pic/w.gif";
    ad00 = new Image();
    ad00.src = prefix+"pic/0ad0.gif";
    ad01 = new Image();
    ad01.src = prefix+"pic/0ad1.gif";
    ad02 = new Image();
    ad02.src = prefix+"pic/0ad2.gif";
    ln1 = new Image();
    ln1.src = prefix+"pic/1.gif";
    ad10 = new Image();
    ad10.src = prefix+"pic/1ad0.gif";
    ad12 = new Image();
    ad12.src = prefix+"pic/1ad2.gif";
    ad20 = new Image();
    ad20.src = prefix+"pic/2ad0.gif";
    ad21 = new Image();
    ad21.src = prefix+"pic/2ad1.gif";
    
    passive = new makeArray(8);
    active = new makeArray(8);
    
    passive[0].src  = prefix+"pic/home.png";
    passive[1].src  = prefix+"pic/research.png";
    passive[2].src  = prefix+"pic/projects.png";
    passive[3].src  = prefix+"pic/publications.png";
    passive[4].src  = prefix+"pic/books.png";
    passive[5].src  = prefix+"pic/scm.png";
    passive[6].src  = prefix+"pic/teaching.png";
    passive[7].src  = prefix+"pic/links.png";
    
    active[0].src  = prefix+"pic/home1.png";
    active[1].src  = prefix+"pic/research1.png";
    active[2].src  = prefix+"pic/projects1.png";
    active[3].src  = prefix+"pic/publications1.png";
    active[4].src  = prefix+"pic/books1.png";
    active[5].src  = prefix+"pic/scm1.png";
    active[6].src  = prefix+"pic/teaching1.png";
    active[7].src  = prefix+"pic/links1.png";
  }
}

function makeArray(n) {
  this.length = n;
  for (var i = 0; i<n; i++)
    this[i] = new Image();
  return this;
}

function onImages(name, index, diag, next_name, next_diag) {
  if ((browser == "Mozilla") && (version >= 3)) {
    document.images[name].src = active[index].src;
    if (diag == "0ad1")
      document.images[name+'-d'].src = ad01.src;
    else if (diag == "2ad1")
      document.images[name+'-d'].src = ad21.src;
    document.images[name+'-ln'].src = ln1.src;
    if (next_diag == "1ad0")
      document.images[next_name+'-d'].src = ad10.src;
    else if (next_diag == "1ad2")
      document.images[next_name+'-d'].src = ad12.src;
  }
}

function offImages(name, index, diag, next_name, next_diag) {
  if ((browser == "Mozilla") && (version >= 3)) {
    document.images[name].src = passive[index].src;
    if (diag == "0ad0")
      document.images[name+'-d'].src = ad00.src;
    else if (diag == "2ad0")
      document.images[name+'-d'].src = ad20.src;
    document.images[name+'-ln'].src = ln0.src;
    if (next_diag == "0ad0")
      document.images[next_name+'-d'].src = ad00.src;
    else if (next_diag == "0ad2")
      document.images[next_name+'-d'].src = ad02.src;
  }
}