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The Window.navigator read-only property returns a reference to the Navigator object, which can be queried for information about the application running the script.

Syntax

navigatorObject = window.navigator

Examples

Example #1: Browser detect and return a string

var sBrowser, sUsrAg = navigator.userAgent;

// The order matters here, and this may report false positives for unlisted browsers.

if (sUsrAg.indexOf("Firefox") > -1) {
  sBrowser = "Mozilla Firefox";
  // "Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:61.0) Gecko/20100101 Firefox/61.0"
} else if (sUsrAg.indexOf("Opera") > -1 || sUsrAg.indexOf("OPR") > -1) {
  sBrowser = "Opera";
  //"Mozilla/5.0 (Macintosh; Intel Mac OS X 10_14_0) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/70.0.3538.102 Safari/537.36 OPR/57.0.3098.106"
} else if (sUsrAg.indexOf("Trident") > -1) {
  sBrowser = "Microsoft Internet Explorer";
  // "Mozilla/5.0 (Windows NT 10.0; WOW64; Trident/7.0; .NET4.0C; .NET4.0E; Zoom 3.6.0; wbx 1.0.0; rv:11.0) like Gecko"
} else if (sUsrAg.indexOf("Edge") > -1) {
  sBrowser = "Microsoft Edge";
  // "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.110 Safari/537.36 Edge/16.16299"
} else if (sUsrAg.indexOf("Chrome") > -1) {
  sBrowser = "Google Chrome or Chromium";
  // "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Ubuntu Chromium/66.0.3359.181 Chrome/66.0.3359.181 Safari/537.36"
} else if (sUsrAg.indexOf("Safari") > -1) {
  sBrowser = "Apple Safari";
  // "Mozilla/5.0 (iPhone; CPU iPhone OS 11_4 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/11.0 Mobile/15E148 Safari/604.1 980x1306"
} else {
  sBrowser = "unknown";
}

alert("You are using: " + sBrowser);

Example #2: Browser detect and return an index

function getBrowserId () {
  var aKeys = ["MSIE", "Firefox", "Safari", "Chrome", "Opera"],
      sUsrAg = navigator.userAgent,
      nIdx = aKeys.length - 1;

  for (nIdx; nIdx > -1 && sUsrAg.indexOf(aKeys[nIdx]) === -1; nIdx--);

  return nIdx;
}

console.log(getBrowserId());

Specifications

Specification Status Comment
HTML Living Standard
The definition of 'Window: navigator' in that specification.
Living Standard  

Browser compatibility

Update compatibility data on GitHub
DesktopMobile
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidEdge MobileFirefox for AndroidOpera for AndroidSafari on iOSSamsung Internet
navigatorChrome Full support YesEdge Full support 12Firefox Full support YesIE ? Opera Full support YesSafari Full support YesWebView Android Full support YesChrome Android Full support YesEdge Mobile ? Firefox Android Full support YesOpera Android Full support YesSafari iOS Full support YesSamsung Internet Android Full support Yes

Legend

Full support  
Full support
Compatibility unknown  
Compatibility unknown