var _userAgent = navigator.userAgent.toLowerCase();
var IE = (_userAgent.indexOf('msie') != -1);
var IE5 = (_userAgent.indexOf('msie 5') != -1);
var IE6 = (_userAgent.indexOf('msie 6') != -1);
var MOZ = (_userAgent.indexOf('gecko') != -1);
var SAFARI = (_userAgent.indexOf('Safari') != -1);
var NS4 = (document.layers);
var IE4 = (document.all);
var MAC = (_userAgent.indexOf("mac") != -1);

var browtyp;
browtyp = (IE4) ? "ie4" : "ns4";