Best way to check for IE less than 9 in JavaScript without library

Question

What would be your fastest  shortest  best  way to detect browser which is IE and version less than 9 in JavaScript  without using jQuery or any add-on libraries

User · Answer

var ie    - 1       true if IE less than 9   This hack is supported in ie5 6 7 8  It is fixed in ie9   so it suits demands of this question   This hack works in all IE compatibility modes   How it works  ie engine treat array with empty element  like this   1   as array with two elements  instead other browsers think that there is only one element  So when we convert this array to number with   operator we do something like that     1  in ie    1  in others  1 and we get NaN in ie and 1 in others  Than we transform it to boolean and reverse value with    Simple  By the way we can use shorter version without   sign  but value will be reversed   This is the shortest hack by now  And I am the author

User · Answer

You are all trying to overcomplicate such simple things  Just use a plain and simple JScript conditional comment  It is the fastest because it adds zero code to non-IE browsers for the detection  and it has compatibility dating back to versions of IE before HTML conditional comments were supported  In short   var IE version  -1   cc on   jscript version        Beware of minifiers  most  if not all  will mistake the special conditional comment for a regular comment  and remove it  Basically  then above code sets the value of IE version to the version of IE you are using  or -1 f you are not using IE  A live demonstration    x000D   x000D  var IE version  -1   cc on   jscript version      x000D  if  IE version   -1   x000D      document write   lt h1 gt You are using Internet Explorer     IE version     lt  h1 gt     x000D    else   x000D      document write   lt h1 gt You are not using a version of Internet Explorer less than 11 lt  h1 gt     x000D    x000D   x000D   x000D

User · Answer

bah to conditional comments   Conditional code all the way      silly IE    lt script type  text javascript  gt     cc on    var IE LT 9      jscript version  lt  9        lt  script gt    Seriously though  just throwing this out there in case it suits you better    they re the same thing  this can just be in a  js file instead of inline HTML  Note  it is entirely coincidental that the jscript version check is  9  here   Setting it to 8  7  etc will NOT check  is IE8   you d need to lookup the jscript versions for those browsers

User · Answer

for what it s worth        if   document addEventListener             alert  you got IE9 or greater            This successfully targets IE 9  because the addEventListener method was supported very early on for every major browser but IE   Chrome  Firefox  Opera  and Safari  MDN Reference  It is supported currently in IE9 and we can expect it to continue to be supported here on out

User · Answer

Using conditional comments  you can create a script block that will only get executed in IE less than 9    lt  -- if lt IE 9   gt   lt script gt  var is ie lt9   true   lt  script gt   lt   endif -- gt     Of course  you could precede this block with a universal block that declares var is ie lt9 false  which this would override for IE less than 9   In that case  you d want to remove the var declaration  as it would be repetitive    EDIT  Here s a version that doesn t rely on in-line script blocks  can be run from an external file   but doesn t use user agent sniffing   Via  cowboy   with document createElement  b    id 4 while innerHTML   lt  -- if gt IE      id    gt 1 lt   endif -- gt   innerHTML gt 0  var ie id gt 5  id 0

User · Answer

I liked Mike Lewis  answer but the code did not pass jslint and I could not understand the funky while loop  My use case is to put up a browser not supported message if less than or equal to IE8   Here is a jslint free version based on Mike Lewis      jslint browser  true      global jQuery     function           use strict       var browserNotSupported    function              var div   document createElement  DIV               http   msdn microsoft com en-us library ms537512 v vs 85  aspx         div innerHTML     lt  -- if lte IE 8  gt  lt I gt  lt  I gt  lt   endif -- gt            return div getElementsByTagName  I   length  gt  0                if  browserNotSupported            jQuery  html   addClass  browserNotSupported   data  browserNotSupported   browserNotSupported

User · Answer

if     MSIE s  d    exec navigator userAgent   0  1   lt  9           IE8 or less      extract IE version with   MSIE s  d    exec navigator userAgent  if it s non-IE browser this will return null so in that case   0 will switch that null to 0  1  will get major version of IE or undefined if it was not an IE browser leading   will convert it into a number  undefined will be converted to NaN comparing NaN with a number will always return false

User · Answer

If I were you I would use conditional compilation or feature detection  Here s another alternative    lt  -- if lt IE 9  gt  lt  -- gt   lt script gt      var LTEIE8   true   lt  script gt   lt  -- lt   endif -- gt

User · Answer

Below is an improvement over James Padolsey s solution   1  It doesn t pollute memory  James  snippet creates 7 unremoved document fragments when detecting IE11  for example   2  It s faster since it checks for a documentMode value before generating markup   3  It s far more legible  especially to beginning JavaScript programmers   Gist link  https   gist github com julianshapiro 9098609      - Behavior  For IE8   we detect the documentMode value provided by Microsoft   - Behavior  For  lt IE8  we inject conditional comments until we detect a match   - Results  In IE  the version is returned  In other browsers  false is returned   - Tip  To check for a range of IE versions  use if   IE    IE  lt  MAX VERSION         var IE    function          if  document documentMode            return document documentMode        else           for  var i   7  i  gt  0  i--                var div   document createElement  div                 div innerHTML     lt  -- if IE     i      gt  lt span gt  lt  span gt  lt   endif -- gt                 if  div getElementsByTagName  span   length                    return i                                     return undefined

User · Answer

Javascript  var ie    function         var undef          v   3          div   document createElement  div            all   div getElementsByTagName  i         while           div innerHTML     lt  -- if gt IE        v       gt  lt i gt  lt  i gt  lt   endif -- gt            all 0              return v  gt  4   v   undef           You can then do   ie  lt  9   By James Panolsey from here  http   james padolsey com javascript detect-ie-in-js-using-conditional-comments

User · Answer

This link contains relevant information on detecting versions of Internet Explorer    http   tanalin com en articles ie-version-js   Example   if  document all  amp  amp   document addEventListener        alert  IE8 or older

User · Answer

I ve decided to go with object detection instead   After reading this  http   www quirksmode org js support html and this  http   diveintohtml5 ep io detect html canvas  I d use something like  if   document createElement  canvas   getContext  alert  what is needed  supported

User · Answer

You could do it in a quick and dirty fashion with a regular expression and  match     if  navigator userAgent match  MSIE s   9 0              ie less than version 9

User · Answer

Does it need to be done in JavaScript   If not then you can use the IE-specific conditional comment syntax    lt  -- if lt IE 9  gt  lt h1 gt Using IE 8 or lower lt  h1 gt  lt   endif -- gt

[javascript] Best way to check for IE less than 9 in JavaScript without library

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