rfc2936.txt

<VC++网络游戏建摸与实现>源代码

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RFC 2936            HTTP MIME Type Handler Detection      September 2000


Appendix A: Browser Version Sniffer Code

  <SCRIPT LANGUAGE="JavaScript">
  <!-- hide JavaScript from non-JavaScript browsers
  // Ultimate client-side JavaScript client sniff.
  // (C) Netscape Communications 1999.
  //     Permission granted to reuse and distribute.
  // Revised 17 May 99 to add is_nav5up and is_ie5up (see below).

  // Everything you always wanted to know about your JavaScript client
  // but were afraid to ask. Creates "is_" variables indicating:
  // (1) browser vendor:
  //     is_nav, is_ie, is_opera
  // (2) browser version number:
  //     is_major (integer indicating major version number: 2, 3, 4 ...)
  //     is_minor (float   indicating full  version number:
  //                                               2.02, 3.01, 4.04 ...)
  // (3) browser vendor AND major version number
  //     is_nav2, is_nav3, is_nav4, is_nav4up, is_nav5, is_nav5up,
  //     is_ie3, is_ie4, is_ie4up
  // (4) JavaScript version number:
  //     is_js (float indicating full JavaScript version number:
  //                                                    1, 1.1, 1.2 ...)
  // (5) OS platform and version:
  //     is_win, is_win16, is_win32, is_win31,
  //     is_win95, is_winnt, is_win98
  //     is_os2
  //     is_mac, is_mac68k, is_macppc
  //     is_unix
  //        is_sun, is_sun4, is_sun5, is_suni86
  //        is_irix, is_irix5, is_irix6
  //        is_hpux, is_hpux9, is_hpux10
  //        is_aix, is_aix1, is_aix2, is_aix3, is_aix4
  //        is_linux, is_sco, is_unixware, is_mpras, is_reliant
  //        is_dec, is_sinix, is_freebsd, is_bsd
  //     is_vms
  //
  // See http://www.it97.de/JavaScript/JS_tutorial/bstat/navobj.html and
  // http://www.it97.de/JavaScript/JS_tutorial/bstat/Browseraol.html
  // for detailed lists of userAgent strings.
  //
  // Note: you don't want your Nav4 or IE4 code to "turn off" or
  // stop working when Nav5 and IE5 (or later) are released, so
  // in conditional code forks, use is_nav4up ("Nav4 or greater")
  // and is_ie4up ("IE4 or greater") instead of is_nav4 or is_ie4
  // to check version in code which you want to work on future
  // versions.




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  // convert all characters to lowercase to simplify testing
  var agt=navigator.userAgent.toLowerCase();

  // *** BROWSER VERSION ***
  // Note: On IE5, these return 4, so use is_ie5up to detect IE5.
  var is_major = parseInt(navigator.appVersion);
  var is_minor = parseFloat(navigator.appVersion);

  // Note: Opera and WebTV spoof Navigator.  We do strict client
  //  detection.  If you want to allow spoofing, take out the tests
  //  for opera and webtv.
  var is_nav  = ((agt.indexOf('mozilla')!=-1)
              && (agt.indexOf('spoofer')==-1)
              && (agt.indexOf('compatible') == -1)
              && (agt.indexOf('opera')==-1)
              && (agt.indexOf('webtv')==-1));
  var is_nav2 = (is_nav && (is_major == 2));
  var is_nav3 = (is_nav && (is_major == 3));
  var is_nav4 = (is_nav && (is_major == 4));
  var is_nav4up = (is_nav && (is_major >= 4));
  var is_navonly      = (is_nav && ((agt.indexOf(";nav") != -1) ||
                        (agt.indexOf("; nav") != -1)) );
  var is_nav5 = (is_nav && (is_major == 5));
  var is_nav5up = (is_nav && (is_major >= 5));

  var is_ie   = (agt.indexOf("msie") != -1);
  var is_ie3  = (is_ie && (is_major < 4));
  var is_ie4  = (is_ie && (is_major == 4)
                       && (agt.indexOf("msie 5.0")==-1) );
  var is_ie4up  = (is_ie  && (is_major >= 4));
  var is_ie5  = (is_ie && (is_major == 4)
                       && (agt.indexOf("msie 5.0")!=-1) );
  var is_ie5up  = (is_ie  && !is_ie3 && !is_ie4);

  // KNOWN BUG: On AOL4, returns false if IE3 is embedded browser
  // or if this is the first browser window opened.  Thus the
  // variables is_aol, is_aol3, and is_aol4 aren't 100% reliable.
  var is_aol   = (agt.indexOf("aol") != -1);
  var is_aol3  = (is_aol && is_ie3);
  var is_aol4  = (is_aol && is_ie4);

  var is_opera = (agt.indexOf("opera") != -1);
  var is_webtv = (agt.indexOf("webtv") != -1);

  // *** JAVASCRIPT VERSION CHECK ***
  var is_js;
  if (is_nav2 || is_ie3) is_js = 1.0
  else if (is_nav3 || is_opera) is_js = 1.1



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  else if ((is_nav4 && (is_minor <= 4.05)) || is_ie4) is_js = 1.2
  else if ((is_nav4 && (is_minor > 4.05)) || is_ie5) is_js = 1.3
  else if (is_nav5) is_js = 1.4
  // NOTE: In the future, update this code when newer versions of JS
  // are released. For now, we try to provide some upward compatibility
  // so that future versions of Nav and IE will show they are at
  // *least* JS 1.x capable. Always check for JS version compatibility
  // with > or >=.
  else if (is_nav && (is_major > 5)) is_js = 1.4
  else if (is_ie && (is_major > 5)) is_js = 1.3
  // HACK: no idea for other browsers;
  //       always check for JS version with > or >=
  else is_js = 0.0;

  // *** PLATFORM ***
  var is_win   = ( (agt.indexOf("win")!=-1) ||
                   (agt.indexOf("16bit")!=-1) );
  // NOTE: On Opera 3.0, the userAgent string includes "Windows 95/NT4"
  // on all Win32, so you can't distinguish between Win95 and WinNT.
  var is_win95 = ((agt.indexOf("win95")!=-1) ||
                  (agt.indexOf("windows 95")!=-1));

  // is this a 16 bit compiled version?
  var is_win16 = ((agt.indexOf("win16")!=-1) ||
             (agt.indexOf("16bit")!=-1) ||
             (agt.indexOf("windows 3.1")!=-1) ||
             (agt.indexOf("windows 16-bit")!=-1) );

  var is_win31 = ((agt.indexOf("windows 3.1")!=-1) ||
                  (agt.indexOf("win16")!=-1) ||
                  (agt.indexOf("windows 16-bit")!=-1));

  // NOTE: Reliable detection of Win98 may not be possible.
  // It appears that:
  //  - On Nav 4.x and before you'll get plain "Windows" in userAgent.
  //  - On Mercury client, the 32-bit version will return "Win98", but
  //    the 16-bit version running on Win98 will still return "Win95".
  var is_win98 = ((agt.indexOf("win98")!=-1) ||
                  (agt.indexOf("windows 98")!=-1));
  var is_winnt = ((agt.indexOf("winnt")!=-1) ||
                  (agt.indexOf("windows nt")!=-1));
  var is_win32 = (is_win95 || is_winnt || is_win98 ||
                  ((is_major >= 4) &&
                   (navigator.platform == "Win32")) ||
                  (agt.indexOf("win32")!=-1) ||
                  (agt.indexOf("32bit")!=-1));

  var is_os2   = ((agt.indexOf("os/2")!=-1) ||



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                  (navigator.appVersion.indexOf("OS/2")!=-1) ||
                  (agt.indexOf("ibm-webexplorer")!=-1));

  var is_mac    = (agt.indexOf("mac")!=-1);
  var is_mac68k = (is_mac && ((agt.indexOf("68k")!=-1) ||
                             (agt.indexOf("68000")!=-1)));
  var is_macppc = (is_mac && ((agt.indexOf("ppc")!=-1) ||
                              (agt.indexOf("powerpc")!=-1)));

  var is_sun   = (agt.indexOf("sunos")!=-1);
  var is_sun4  = (agt.indexOf("sunos 4")!=-1);
  var is_sun5  = (agt.indexOf("sunos 5")!=-1);
  var is_suni86= (is_sun && (agt.indexOf("i86")!=-1));
  var is_irix  = (agt.indexOf("irix") !=-1);    // SGI
  var is_irix5 = (agt.indexOf("irix 5") !=-1);
  var is_irix6 = ((agt.indexOf("irix 6") !=-1) ||
                  (agt.indexOf("irix6") !=-1));
  var is_hpux  = (agt.indexOf("hp-ux")!=-1);
  var is_hpux9 = (is_hpux && (agt.indexOf("09.")!=-1));
  var is_hpux10= (is_hpux && (agt.indexOf("10.")!=-1));
  var is_aix   = (agt.indexOf("aix") !=-1);      // IBM
  var is_aix1  = (agt.indexOf("aix 1") !=-1);
  var is_aix2  = (agt.indexOf("aix 2") !=-1);
  var is_aix3  = (agt.indexOf("aix 3") !=-1);
  var is_aix4  = (agt.indexOf("aix 4") !=-1);
  var is_linux = (agt.indexOf("inux")!=-1);
  var is_sco   = (agt.indexOf("sco")!=-1) ||
                 (agt.indexOf("unix_sv")!=-1);
  var is_unixware = (agt.indexOf("unix_system_v")!=-1);
  var is_mpras    = (agt.indexOf("ncr")!=-1);
  var is_reliant  = (agt.indexOf("reliantunix")!=-1);
  var is_dec   = ((agt.indexOf("dec")!=-1) ||
         (agt.indexOf("osf1")!=-1) ||
         (agt.indexOf("dec_alpha")!=-1) ||
         (agt.indexOf("alphaserver")!=-1) ||
         (agt.indexOf("ultrix")!=-1) ||
         (agt.indexOf("alphastation")!=-1));
  var is_sinix = (agt.indexOf("sinix")!=-1);
  var is_freebsd = (agt.indexOf("freebsd")!=-1);
  var is_bsd = (agt.indexOf("bsd")!=-1);
  var is_unix  = ((agt.indexOf("x11")!=-1) || is_sun ||
               is_irix || is_hpux ||
               is_sco ||is_unixware || is_mpras || is_reliant ||
               is_dec || is_sinix || is_aix || is_linux ||
               is_bsd || is_freebsd);

  var is_vms   = ((agt.indexOf("vax")!=-1) ||
                  (agt.indexOf("openvms")!=-1));



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  </SCRIPT>

Authors' Addresses

   Donald E. Eastlake 3rd
   Motorola
   140 Forest Avenue
   Hudson, MA 01749 USA

   Phone: [phone](h)
          [phone](w)
   Fax:   [phone](w)
   EMail: [e-mail]


   Chris J. Smith
   Royal Bank of Canada
   277 Front Street West
   Toronto, Ontario M5V 3A4 CANADA

   Phone: [phone]
   Fax:   [phone]
   EMail: [e-mail]


   David M. Soroka
   IBM
   Raleigh, NC

   Phone: [phone]
   Fax:   [phone]
   EMail: [e-mail]



















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Full Copyright Statement

   Copyright (C) The Internet Society (2000).  All Rights Reserved.

   This document and translations of it may be copied and furnished to
   others, and derivative works that comment on or otherwise explain it
   or assist in its implementation may be prepared, copied, published
   and distributed, in whole or in part, without restriction of any
   kind, provided that the above copyright notice and this paragraph are
   included on all such copies and derivative works.  However, this
   document itself may not be modified in any way, such as by removing
   the copyright notice or references to the Internet Society or other
   Internet organizations, except as needed for the purpose of
   developing Internet standards in which case the procedures for
   copyrights defined in the Internet Standards process must be
   followed, or as required to translate it into languages other than
   English.

   The limited permissions granted above are perpetual and will not be
   revoked by the Internet Society or its successors or assigns.

   This document and the information contained herein is provided on an
   "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
   TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
   BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION
   HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.

Acknowledgement

   Funding for the RFC Editor function is currently provided by the
   Internet Society.



















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