Authors:Peter Higgins, Ben Lowery

dojo/sniff is the main Dojo module for browser feature detection. Feature detection is an important consideration when writing code. It allows more maintainable code, better user experience, forward-compatibility and more performant code. The dojo/has API is the main Dojo mechanism for accomplishing this and dojo/sniff leverages this.

When leveraged with Dojo’s Builder unused code, for non-targeted browsers, can be removed and decrease the size and increase the performance of your code.


The module can be used two ways, because the module add features to dojo/has and it also returns dojo/has as the return value of the module. Both the examples below are functionally the same:

require(["dojo/sniff"], function(sniff){
    // Do something specific for IE.
require(["dojo/has", "dojo/sniff"], function(has){
    // Do something specific for IE.

The module defines the following has-features:

Feature Notes
air Detects Adobe AIR Environments
webkit Detects Webkit based environments 1.3+
chrome Detects Google Chrome 1.3+
mac Detects if the platform is Mac OSX
quirks If the browser is running in “quirks” mode
ios Detects iOS based devices [1]
android Detects Android based devices [1]
wii Detects if running on a Nintendo Wii
[1](1, 2) See dojox/mobile/sniff for additional mobile platform detection.

Each feature will only return a truthy value if the specified browser is being used. For example if you are using Internet Explorer has("ie") will only return a truthy value, where as has("chrome") will return false.

The value returned, where appropriate, will provide the version number of the browser, so specific code checks and be done for versions. For example:

require(["dojo/has", "dojo/sniff"], function(has){
  if(has("ie") <= 6){ // only IE6 and below
    // ...

  if(has("ff") < 3){ // only Firefox 2.x and lower
    // ...

  if(has("ie") == 7){ // only IE7
    // ...


Basic browser detection example.

require(["dojo/has", // alias has API to "has"
    "dojo/_base/array", // alias array api to "arrayUtil"
    "dojo/dom", // alias DOM api to "dom"
    "dojo/_base/sniff", // load browser-related has feature tests
    "dojo/domReady!" // wait until DOM is loaded
], function(has, array, dom){

  function makeFancyAnswer(who){
      return "Yes, it's version " + has(who);
      return "No";

  function makeAtLeastAnswer(who, version){
    var answer = (has(who) >= version) ? "Yes" : "No";
    dom.byId("isAtLeast" + who + version).innerHTML = answer;

  array.forEach(["ie", "mozilla", "ff", "opera", "webkit", "chrome"], function(n){
    dom.byId("answerIs" + n).innerHTML = makeFancyAnswer(n);

  makeAtLeastAnswer("ie", 7);
  makeAtLeastAnswer("ff", 3);
  makeAtLeastAnswer("opera", 9);

  <dt>Is this Internet Explorer?</dt>
  <dd id="answerIsie"></dd>
  <dt>Is this Firefox?</dt>
  <dd id="answerIsff"></dd>
  <dt>Is this Mozilla?</dt>
  <dd id="answerIsmozilla"></dd>
  <dt>Is this Opera?</dt>
  <dd id="answerIsopera"></dd>
  <dt>Is this WebKit? (Dojo 1.3)</dt>
  <dd id="answerIswebkit"></dd>
  <dt>Is this Chrome? (Dojo 1.3)</dt>
  <dd id="answerIschrome"></dd>
  <dt>Is this at least IE 7?</dt>
  <dd id="isAtLeastie7"></dd>
  <dt>Is this at least Firefox 3?</dt>
  <dd id="isAtLeastff3"></dd>
  <dt>Is this at least Opera 9?</dt>
  <dd id="isAtLeastopera9"></dd>

See Also

Table of Contents

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