// Browser types
var btName;
var btOld, btOp, btIE4, btNN4, btDOM;
var bstOp, bstIE, bstN6,
    bstById, bstDAll, bstLayers,
    bstWin;

var IE,NN;
//var NN = (document.layers) ? 1 : 0;
var Opera = (navigator.userAgent.indexOf('Opera') >= 0)? true : false;
var IE = (document.all && !Opera)? true : false;
var NN6= (document.getElementById && !IE && !Opera)?true:false;

function detectBrowserType() {
  btName="";
  btOld=btOp=btIE4=btNN4=btDOM=false;
  bstOp=bstN6=bstById=bstDAll=bstLayers
       =bstWin=false;

  var ua=navigator.userAgent;

  if ( ua.indexOf("indows")>0 ) bstWin=true;

  if ( document.all ) bstDAll=true;
  if ( document.getElementById ) bstById=true;
  if ( ua.indexOf("Opera")>=0 ) bstOp=true;
  bstIE=(bstDAll&&!bstOp);

  if ( document.layers ) { bstLayers=btNN4=true; btName="NN4"; }
  else if ( bstById && document.createElement && !bstOp) {
    btDOM=true; btName="DOM";
    bstN6 = (ua.indexOf("Gecko")>0);
  }
  else if ( bstDAll ) { btIE4=true; btName="IE4"; }
  else if ( bstById && bstOp ) { btOp=true; btName="Opera"; }
  else btOld=true;

  IE=bstIE;
  NN=bstLayers;

  return !btOld;
}

detectBrowserType();