function BrowserDetect() {

  var ua = navigator.userAgent.toLowerCase();

  this.isStrict = window.document.compatMode && window.document.compatMode == "CSS1Compat" ? true : false;

  // browser name
  this.isGecko     = (ua.indexOf('gecko') != -1 && ua.indexOf('safari') == -1);
  this.isMozilla   = (this.isGecko && ua.indexOf('gecko/') + 14 == ua.length);
  this.isNS        = ((this.isGecko) ? (ua.indexOf('netscape') != -1) : ((ua.indexOf('mozilla') != -1) && (ua.indexOf('spoofer') == -1) && (ua.indexOf('compatible') == -1) && (ua.indexOf('opera') == -1) && (ua.indexOf('webtv') == -1) && (ua.indexOf('hotjava') == -1)));
  this.isIE        = ((ua.indexOf('msie') != -1) && (ua.indexOf('opera') == -1) && (ua.indexOf('webtv') == -1) );
  this.isSafari    = (ua.indexOf('safari') != - 1);
  this.isOpera     = (ua.indexOf('opera') != -1);
  this.isKonqueror = (ua.indexOf('konqueror') != -1 && !this.isSafari);
  this.isIcab      = (ua.indexOf('icab') != -1);
  this.isAol       = (ua.indexOf('aol') != -1);

  // spoofing and compatible browsers
  this.isIECompatible = ((ua.indexOf('msie') != -1) && !this.isIE);
  this.isNSCompatible = ((ua.indexOf('mozilla') != -1) && !this.isNS && !this.isMozilla);

  // browser version
  this.versionMinor = parseFloat(navigator.appVersion);

  // correct version number
  if(this.isNS && this.isGecko) {
    this.versionMinor = parseFloat(ua.substring( ua.lastIndexOf('/') + 1));
  } else if(this.isIE && this.versionMinor >= 4) {
    this.versionMinor = parseFloat(ua.substring( ua.indexOf('msie ') + 5));
  } else if(this.isMozilla) {
    this.versionMinor = parseFloat(ua.substring( ua.indexOf('rv:') + 3));
  } else if(this.isSafari) {
    this.versionMinor = parseFloat(ua.substring( ua.lastIndexOf('/') + 1));
  } else if(this.isOpera) {
    if(ua.indexOf('opera/') != -1) {
      this.versionMinor = parseFloat(ua.substring( ua.indexOf('opera/') + 6));
    } else {
      this.versionMinor = parseFloat(ua.substring( ua.indexOf('opera ') + 6));
    }
  } else if(this.isKonqueror) {
    this.versionMinor = parseFloat(ua.substring( ua.indexOf('konqueror/') + 10));
  } else if(this.isIcab) {
    if(ua.indexOf('icab/') != -1) {
      this.versionMinor = parseFloat(ua.substring( ua.indexOf('icab/') + 6));
    } else {
      this.versionMinor = parseFloat(ua.substring( ua.indexOf('icab ') + 6));
    }
  }

  this.versionMajor = parseInt(this.versionMinor);
  this.geckoVersion = ((this.isGecko) ? ua.substring((ua.lastIndexOf('gecko/') + 6), (ua.lastIndexOf('gecko/') + 14)) : -1);

  //  GECKO REVISION
  this.geckoRevision = -1;
  if(this.isGecko) {
    temp = ua.split("rv:");
    this.geckoRevision = parseFloat(temp[1]);
  }

  // dom support
  this.isDOM1 = (document.getElementById);
  this.isDOM2Event = (document.addEventListener && document.removeEventListener);

  // css compatibility mode
  this.mode = document.compatMode ? document.compatMode : 'BackCompat';

  // platform
  this.isWin   = (ua.indexOf('win') != -1);
  this.isWin32 = (this.isWin && (ua.indexOf('95') != -1 || ua.indexOf('98') != -1 || ua.indexOf('nt') != -1 || ua.indexOf('win32') != -1 || ua.indexOf('32bit') != -1 || ua.indexOf('xp') != -1));
  this.isMac   = (ua.indexOf('mac') != -1);
  this.isUnix  = (ua.indexOf('unix') != -1 || ua.indexOf('sunos') != -1 || ua.indexOf('bsd') != -1 || ua.indexOf('x11') != -1);
  this.isLinux = (ua.indexOf('linux') != -1);

  // specific browser shortcuts
  this.isNS4x = (this.isNS && this.versionMajor == 4);
  this.isNS40x = (this.isNS4x && this.versionMinor < 4.5);
  this.isNS47x = (this.isNS4x && this.versionMinor >= 4.7);
  this.isNS4up = (this.isNS && this.versionMinor >= 4);
  this.isNS6x = (this.isNS && this.versionMajor == 6);
  this.isNS6up = (this.isNS && this.versionMajor >= 6);
  this.isNS7x = (this.isNS && this.versionMajor == 7);
  this.isNS7up = (this.isNS && this.versionMajor >= 7);

  this.isIE4x = (this.isIE && this.versionMajor == 4);
  this.isIE4up = (this.isIE && this.versionMajor >= 4);
  this.isIE5x = (this.isIE && this.versionMajor == 5);
  this.isIE55 = (this.isIE && this.versionMinor == 5.5);
  this.isIE55up = (this.isIE && this.versionMinor >= 5.5);
  this.isIE5up = (this.isIE && this.versionMajor >= 5);
  this.isIE6x = (this.isIE && this.versionMajor == 6);
  this.isIE6up = (this.isIE && this.versionMajor >= 6);

  this.isIE4xMac = (this.isIE4x && this.isMac);
}

var browser = new BrowserDetect();