function initNav()
      {
        var nav = document.getElementById('nav');
        var anchors = nav.getElementsByTagName('a');
        for (var i = 0; i < anchors.length; i++)
        {
          var anchor = anchors[i];
          var img = anchor.childNodes[0];
          if (img.tagName == 'img')
            if ((img.src.substring(img.src.length - 9) != '_over.gif') && (img.src.substring(img.src.length - 8) != '-off.gif') && (img.src.substring(img.src.length - 7) != '-on.gif'))
            {
              var new_src = img.src.substring(0, img.src.length - 4) + '_over.gif';
              anchor.setAttribute('orig_src', img.src);
              anchor.setAttribute('new_src', new_src);
              anchor.onmouseout = new Function('var img = this.childNodes[0]; img.src = this.getAttribute(\'orig_src\')');
              anchor.onmouseover = new Function('var img = this.childNodes[0]; img.src = this.getAttribute(\'new_src\')');
              var img = new Image();
              img.src = new_src;
            }
        }
      }