var browser;
   strAppVersion = navigator.appVersion;
   strPattern    = /MSIE\s*(\d.\d+)/;
   strPattern.exec(strAppVersion);
   if (RegExp.$1 >= 5.5 && navigator.userAgent.indexOf("Opera") == -1)
     { browser = 1;}
   else
     {
       if (navigator.userAgent.indexOf('Firefox') != -1) { browser = 2; }
       if (navigator.userAgent.indexOf('Opera')   != -1) { browser = 3; }
       if (navigator.userAgent.indexOf('Safari')  != -1) { browser = 4; }
       if (navigator.userAgent.indexOf('Chrome')  != -1) { browser = 5; }
     }