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a browser detector
JavaScript Makefile
Latest commit 569af9b May 24, 2016 @lancedikson lancedikson add issue temlate


A Browser detector. Because sometimes, there is no other way, and not even good modern browsers always provide good feature detection mechanisms.

bowser ci

So... it works like this:

if (bowser.msie && bowser.version <= 6) {
  alert('Hello China');

1.1.0 breaking changes

We don't save built script in the repo anymore. The main file (src/bowser.js) is available through NPM or Bower. Also you can download minified file from the release page.

1.0.0 breaking changes

browser = require('bowser').browser; becomes browser = require('bowser');

Bowser Flags

Your mileage may vary, but these flags should be set. See Contributing below.

alert('Hello ' + + ' ' + bowser.version);

All detected browsers

These flags are set for all detected browsers:

  • name - A human readable name for this browser. E.g. 'Chrome', ''
  • version - Version number for the browser. E.g. '32.0'

For unknown browsers, Bowser makes a best guess from the UA string. So, these may not be set.

Rendering engine flags

If detected, one of these flags may be set to true:

  • webkit - Chrome 0-27, Android <4.4, iOs, BB, etc.
  • blink - Chrome >=28, Android >=4.4, Opera, etc.
  • gecko - Firefox, etc.
  • msie - IE <= 11
  • msedge - IE > 11

Safari, Chrome and some other minor browsers will report that they have webkit engines. Firefox and Seamonkey will report that they have gecko engines.

if (bowser.webkit) {
  // do stuff with safari & chrome & opera & android & blackberry & webos & silk

Device flags

If detected, one of these flags may be set to true:

  • mobile - All detected mobile OSes are additionally flagged mobile, unless it's a tablet
  • tablet - If a tablet device is detected, the flag tablet is set instead of mobile.

Browser flags

If detected, one of these flags may be set to true. The rendering engine flag is shown in []'s:

  • chrome - [webkit|blink]
  • firefox - [gecko]
  • msie
  • msedge
  • safari - [webkit]
  • android - native browser - [webkit|blink]
  • ios - native browser - [webkit]
  • opera - [blink if >=15]
  • phantom - [webkit]
  • blackberry - native browser - [webkit]
  • webos - native browser - [webkit]
  • silk - Amazon Kindle browser - [webkit]
  • bada - [webkit]
  • tizen - [webkit]
  • seamonkey - [gecko]
  • sailfish - [gecko]
  • ucbrowser — [webkit]
  • qupzilla — [webkit]
  • vivaldi — [blink]
  • sleipnir — [blink]
  • kMeleon — [gecko]

For all detected browsers the browser version is set in the version field.

OS Flags

If detected, one of these flags may be set to true:

  • mac
  • windows - other than Windows Phone
  • windowsphone
  • linux - other than android, chromeos, webos, tizen, and sailfish
  • chromeos
  • android
  • ios - also sets one of iphone/ipad/ipod
  • blackberry
  • firefoxos
  • webos - may also set touchpad
  • bada
  • tizen
  • sailfish

osversion may also be set:

  • osversion - for Android, iOS, Windows Phone, WebOS, Bada, and Tizen. If included in UA string.

iOS is always reported as ios and additionally as iphone/ipad/ipod, whichever one matches best. If WebOS device is an HP TouchPad the flag touchpad is additionally set.

Browser capability grading

One of these flags may be set:

  • a - This browser has full capabilities
  • c - This browser has degraded capabilities. Serve simpler version
  • x - This browser has minimal capabilities and is probably not well detected.

There is no b. For unknown browsers, none of these flags may be set.

Ender Support


"dependencies": {
  "bowser": "x.x.x"
if (require('bowser').chrome) {
  alert('Hello Silicon Valley')


If you'd like to contribute a change to bowser, modify the files in src/, then run the following (you'll need node + npm installed):

$ npm install
$ make test

Please do not check-in the built files bowser.js and bowser.min.js in pull requests.

Adding tests

See the list in src/useragents.js with example user agents and their expected bowser object.

Whenever you add support for new browsers or notice a bug / mismatch, please update the list and check if all tests are still passing.


Licensed as MIT. All rights not explicitly granted in the MIT license are reserved. See the included LICENSE file for more details.

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