src/scss/bootstrap-4.0.0-alpha.6/docs/assets/js/ie-emulation-modes-warning.js

   1 // NOTICE!! DO NOT USE ANY OF THIS JAVASCRIPT
   2 // IT'S JUST JUNK FOR OUR DOCS!
   3 // ++++++++++++++++++++++++++++++++++++++++++
   4 /*!
   5  * Copyright 2014-2015 The Bootstrap Authors
   6  * Copyright 2014-2015 Twitter, Inc.
   7  *
   8  * Licensed under the Creative Commons Attribution 3.0 Unported License. For
   9  * details, see https://creativecommons.org/licenses/by/3.0/.
  10  */
  11 // Intended to prevent false-positive bug reports about Bootstrap not working properly in old versions of IE due to folks testing using IE's unreliable emulation modes.
  12 (function () {
  13   'use strict'
  14
  15   function emulatedIEMajorVersion() {
  16     var groups = /MSIE ([0-9.]+)/.exec(window.navigator.userAgent)
  17     if (groups === null) {
  18       return null
  19     }
  20     var ieVersionNum = parseInt(groups[1], 10)
  21     var ieMajorVersion = Math.floor(ieVersionNum)
  22     return ieMajorVersion
  23   }
  24
  25   function actualNonEmulatedIEMajorVersion() {
  26     // Detects the actual version of IE in use, even if it's in an older-IE emulation mode.
  27     // IE JavaScript conditional compilation docs: https://msdn.microsoft.com/library/121hztk3%28v=vs.94%29.aspx
  28     // @cc_on docs: https://msdn.microsoft.com/library/8ka90k2e%28v=vs.94%29.aspx
  29     var jscriptVersion = new Function('/*@cc_on return @_jscript_version; @*/')()
  30     if (jscriptVersion === undefined) {
  31       return 11 // IE11+ not in emulation mode
  32     }
  33     if (jscriptVersion < 9) {
  34       return 8 // IE8 (or lower; haven't tested on IE<8)
  35     }
  36     return jscriptVersion // IE9 or IE10 in any mode, or IE11 in non-IE11 mode
  37   }
  38
  39   var ua = window.navigator.userAgent
  40   if (ua.indexOf('Opera') > -1 || ua.indexOf('Presto') > -1) {
  41     return // Opera, which might pretend to be IE
  42   }
  43   var emulated = emulatedIEMajorVersion()
  44   if (emulated === null) {
  45     return // Not IE
  46   }
  47   var nonEmulated = actualNonEmulatedIEMajorVersion()
  48
  49   if (emulated !== nonEmulated) {
  50     window.alert('WARNING: You appear to be using IE' + nonEmulated + ' in IE' + emulated + ' emulation mode.\nIE emulation modes can behave significantly differently from ACTUAL older versions of IE.\nPLEASE DON\'T FILE BOOTSTRAP BUGS based on testing in IE emulation modes!')
  51   }
  52 }())