// Create global variables for browser type
    var isIE = new Boolean(false);
    var isNav = new Boolean(false);
    var unSupported = new Boolean(false);
    var layer = new String();
    var style = new String();
    // Determine if the browser is Internet Explorer, Navigator,
    // or other. Also, set the layer variable depending on the
    // type of access it needs.
    function checkBrowser(){
      if(navigator.userAgent.indexOf("MSIE") != -1){
        isIE = true;
        layer = ".all";
        style = ".style";
      }else if(navigator.userAgent.indexOf("Nav") != -1){
        isNav = true;
        layer = ".layers";
        style = "";
      }else{
        unSupported = true;
      }
     }
    // Take the state passed in, and change it.
    function changeState(layerRef, state){
      eval("document" + layer + "['" + layerRef + "']" + style + ".visibility = '" + state + "'");
    }