// Detección de Navegador

   is_dom = (document.getElementById) ? true : false;
   is_exp = (document.all) ? true : false;
   is_exp4 = is_exp && !is_dom;
   is_exp5 = is_exp && is_dom;

   is_mac = (navigator.appVersion.indexOf("Mac") != -1);
   is_mac_exp4 = is_exp4 && is_mac;
   is_mac_exp5 = is_exp5 && is_mac;

   is_net = navigator.appName == ("Netscape");
   is_net4 = (document.layers) ? true : false;
   is_net6 = navigator.vendor == ("Netscape6");

   is_ok = (is_dom || is_net4 || (is_exp && !is_mac_exp4)); // si vale true, todo debería funcionar
   if(!is_ok) evento = null;

   function abrir_dhtml() {return};
   function cerrar_dhtml() {return};

   layersHide = new Array();
   layersTimeout = new Array();

function forceShowLayer (name) {
    if (is_ok) {
        layersHide[name] = false;
        layerHandler (name);
        layersHide[name] = true;
        layersTimeout[name] = setTimeout ("layerHandler('" + name + "')", 500);
    }
}

function showLayer (name,on) {
        if (is_ok) {
          if (on) {
            if (layersHide[name]) clearTimeout (layersTimeout[name]);
            layersHide[name] = false;
            layerHandler (name);
          }
          else{
            layersHide[name] = true;
            layersTimeout[name] = setTimeout ("layerHandler('" + name + "')", 100);
          }
      }
  }
  
function layerHandler(name) {
        if (layersHide[name]) {
          if (is_net4) {
             document.layers[name].visibility = "hide";
          } else if (is_dom) {
             document.getElementById(name).style.visibility = "hidden";
          } else {
             document.all[name].style.visibility = "hidden";
          }
      } else {
          if (is_net4) {
             document.layers[name].visibility = "show";
          } else if (is_dom) {
             document.getElementById(name).style.visibility = "visible";
          } else {
             document.all[name].style.visibility = "visible";
          }
      }
   }

function moveLayer(name,x,y) {
        if (is_ok) {
                if (is_net4) {
                        screenWidth = window.innerWidth;
                        document.layers[name].left = x;
                        document.layers[name].top = y; // Direferencia entre navegadores
                } else if (is_dom) {
                        screenWidth = (document.body.clientWidth ? document.body.clientWidth : window.innerWidth) + 18;
                        document.getElementById(name).style.left = x;
                        document.getElementById(name).style.top = y;
                } else {
                        screenWidth = document.body.clientWidth + 18;
                        document.all[name].style.pixelLeft = x;
                        document.all[name].style.pixelTop = y;
                }
        }
}

function isLayerActive (name) {
    var visibility;
    if (is_net4) visibility = document.layers[name].visibility;
    else if (is_dom) visibility = document.getElementById(name).style.visibility;
    else visibility = document.all[name].style.visibility;

    return (visibility == "visible")? true: false;
}