var topNavElms = new Array('b1', 'b2', 'b3', 'b4', 'b5', 'b6');

var timeoutId = null;

var USE_FADE = true;
var TIMEOUT = 100; //  milliseconds
var CROSS_FADE_DURATION = 0.01;

var ns4 = (navigator.appName == 'Netscape' && parseInt(navigator.appVersion) == 4);
var ns6 = (document.getElementById)? true : false;
var ie4 = (document.all)? true : false;

if (document.images) {
   b1over          = new Image();
   b1over.src      = "/images/tab_home_over.gif;jsessionid=DC692113B5BFB1445047646A3D8A5137";
   b1off           = new Image() ;
   b1off.src       = "/images/tab_home_off.gif;jsessionid=DC692113B5BFB1445047646A3D8A5137";

   b2over          = new Image();
   b2over.src      = "/images/tab_res_over.gif;jsessionid=DC692113B5BFB1445047646A3D8A5137";
   b2off           = new Image() ;
   b2off.src       = "/images/tab_res_off.gif;jsessionid=DC692113B5BFB1445047646A3D8A5137";

   b3over          = new Image();
   b3over.src      = "/images/tab_rent_over.gif;jsessionid=DC692113B5BFB1445047646A3D8A5137";
   b3off           = new Image() ;
   b3off.src       = "/images/tab_rent_off.gif;jsessionid=DC692113B5BFB1445047646A3D8A5137";

   b4over          = new Image();
   b4over.src      = "/images/tab_land_over.gif;jsessionid=DC692113B5BFB1445047646A3D8A5137";
   b4off           = new Image() ;
   b4off.src       = "/images/tab_land_off.gif;jsessionid=DC692113B5BFB1445047646A3D8A5137";

   b5over          = new Image();
   b5over.src      = "/images/tab_news_over.gif;jsessionid=DC692113B5BFB1445047646A3D8A5137";
   b5off           = new Image() ;
   b5off.src       = "/images/tab_news_off.gif;jsessionid=DC692113B5BFB1445047646A3D8A5137";

   b6over          = new Image();
   b6over.src      = "/images/tab_taos_over.gif;jsessionid=DC692113B5BFB1445047646A3D8A5137";
   b6off           = new Image() ;
   b6off.src       = "/images/tab_taos_off.gif;jsessionid=DC692113B5BFB1445047646A3D8A5137";
}

function is_ie() {
  var agent = navigator.userAgent.toLowerCase();
  return ((agent.indexOf("msie") != -1) && (agent.indexOf("opera") == -1));
}

function buttonOver(id) {
   if (document.images) {
      var btn = document[id];
      if (btn.src.indexOf("_on.gif") == -1) {
        if (document.all && USE_FADE == true) {
          btn.filters.blendTrans.Stop();
        }
  
        btn.src = eval(id + "over.src");
      }
   }
}

function buttonOff(id) {
   if (document.images) {
      var btn = document[id];
      if (btn.src.indexOf("_on.gif") == -1) {
        if (USE_FADE == true) {
          buttonTrans(id, false);
        }
        else {
          btn.src = eval(id + "off.src");
        }
      }
   }
}

// image transition function (compatibility unknown)
function buttonTrans(id, turnOn) {
  var btn = document[id];

  if (document.all) {
    btn.style.filter = "blendTrans(duration=0)";
    btn.style.filter = "blendTrans(duration=CROSS_FADE_DURATION)";
    btn.filters.blendTrans.Apply();
  }

  if (turnOn) {
    btn.src = eval(id + "over.src");
  }
  else {
    btn.src = eval(id + "off.src");
  }

  if (document.all) {
    btn.filters.blendTrans.Play();
  }
}

function show(id) {
  var d = window.document;

  if (ns4) obj = d.id;
  if (ns6) obj = d.getElementById(id);

  if (ns4) obj.visibility = "show";
  else if (ie4) d.all[id].style.visibility = "visible";
  else if (ns6) obj.style.visibility = "visible";
}

function hide(id) {
  var d = window.document;

  if (ns4) obj = d.id;
  if (ns6) obj = d.getElementById(id);

  if (ns4) obj.visibility = "hide";
  else if (ie4) d.all[id].style.visibility = "hidden";
  else if (ns6) obj.style.visibility = "hidden";
}

function hideNav() {
  for (i = 0; i < topNavElms.length; i++) {
    buttonOff(topNavElms[i]);
  }
}

function showNav(id) {
  if (timeoutId != null) {
    clearTimeout(timeoutId);
  }

  hideNav();
  buttonOver(id);
}

function outNav() {
  timeoutId = setTimeout("hideNav()", TIMEOUT);
}