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cou929/detect-private-browsing.js

Last active May 1, 2024 21:07
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Detect private browsing mode (InPrivate Browsing or Incognito).
Raw
detect-private-browsing.js
function retry(isDone, next) {
var current_trial = 0, max_retry = 50, interval = 10, is_timeout = false;
var id = window.setInterval(
function() {
if (isDone()) {
window.clearInterval(id);
next(is_timeout);
}
if (current_trial++ > max_retry) {
window.clearInterval(id);
is_timeout = true;
next(is_timeout);
}
},
10
);
}
function isIE10OrLater(user_agent) {
var ua = user_agent.toLowerCase();
if (ua.indexOf('msie') === 0 && ua.indexOf('trident') === 0) {
return false;
}
var match = /(?:msie|rv:)\s?([\d\.]+)/.exec(ua);
if (match && parseInt(match[1], 10) >= 10) {
return true;
}
return false;
}
function detectPrivateMode(callback) {
var is_private;
if (window.webkitRequestFileSystem) {
window.webkitRequestFileSystem(
window.TEMPORARY, 1,
function() {
is_private = false;
},
function(e) {
console.log(e);
is_private = true;
}
);
} else if (window.indexedDB && /Firefox/.test(window.navigator.userAgent)) {
var db;
try {
db = window.indexedDB.open('test');
} catch(e) {
is_private = true;
}
if (typeof is_private === 'undefined') {
retry(
function isDone() {
return db.readyState === 'done' ? true : false;
},
function next(is_timeout) {
if (!is_timeout) {
is_private = db.result ? false : true;
}
}
);
}
} else if (isIE10OrLater(window.navigator.userAgent)) {
is_private = false;
try {
if (!window.indexedDB) {
is_private = true;
}
} catch (e) {
is_private = true;
}
} else if (window.localStorage && /Safari/.test(window.navigator.userAgent)) {
try {
window.localStorage.setItem('test', 1);
} catch(e) {
is_private = true;
}
if (typeof is_private === 'undefined') {
is_private = false;
window.localStorage.removeItem('test');
}
}
retry(
function isDone() {
return typeof is_private !== 'undefined' ? true : false;
},
function next(is_timeout) {
callback(is_private);
}
);
}
Raw
example.html
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
</head>
<body>
<div id="result"></div>
<script src="detect-private-browsing.js"></script>
<script>
detectPrivateMode(
function(is_private) {
document.getElementById('result').innerHTML = typeof is_private === 'undefined' ? 'cannot detect' : is_private ? 'private' : 'not private';
}
);
</script>
</body>
</html>
@gremz
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gremz commented Nov 16, 2018

@tormod17 where/how are you trying to attempting this check? Any chance you're doing this in an iframe?

@gu10214
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gu10214 commented Feb 8, 2019

False positive on iOS 12+ as tormod17 mentioned, are we playing whack a mole here with each iOS release/patch?

@narcisso
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narcisso commented Apr 2, 2019 

function isPrivate(callback) {
  callback || (callback = function(){});
  var fs = window.RequestFileSystem || window.webkitRequestFileSystem;

  if(fs){
    return fs(window.TEMPORARY, 1, callback.bind(this, false), callback.bind(this, true));
  }

  if(window.indexedDB && /Firefox/.test(window.navigator.userAgent)){
    try {
      var db       = window.indexedDB.open('test');
      var tryes    = 0;
      var interval = limit = 10;

      var wait = function(check){
        if(tryes >= limit){ return callback(true); } // Give up
        return window.setTimeout(check, ++tryes * interval);
      }

      var evaluate = function(){
        return db.readyState === 'done' ? callback(!db.result) : wait(evaluate);
      }

      return wait(evaluate);
    } catch (e) {
      return callback(true);
    }
  }

  if (!!window.navigator.userAgent.match(/(MSIE|Trident|Edge)/)){
    try {
      return callback(!window.indexedDB);
    } catch (e) {
      return callback(true);
    }
  }

  try {
    window.openDatabase(null, null, null, null);
    return callback(false);
  } catch (e) {
    return callback(true);
  }
}

isPrivate( function(isPrivate) {
  console.log('Private mode ===>', isPrivate);
});

@0c0c0f
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0c0c0f commented May 13, 2019 

function isPrivate(callback) {
  callback || (callback = function(){});
  var fs = window.RequestFileSystem || window.webkitRequestFileSystem;

  if(fs){
    return fs(window.TEMPORARY, 1, callback.bind(this, false), callback.bind(this, true));
  }

  if(window.indexedDB && /Firefox/.test(window.navigator.userAgent)){
    try {
      var db       = window.indexedDB.open('test');
      var tryes    = 0;
      var interval = limit = 10;

      var wait = function(check){
        if(tryes >= limit){ return callback(true); } // Give up
        return window.setTimeout(check, ++tryes * interval);
      }

      var evaluate = function(){
        return db.readyState === 'done' ? callback(!db.result) : wait(evaluate);
      }

      return wait(evaluate);
    } catch (e) {
      return callback(true);
    }
  }

  if (!!window.navigator.userAgent.match(/(MSIE|Trident|Edge)/)){
    try {
      return callback(!window.indexedDB);
    } catch (e) {
      return callback(true);
    }
  }

  try {
    window.openDatabase(null, null, null, null);
    return callback(false);
  } catch (e) {
    return callback(true);
  }
}

isPrivate( function(isPrivate) {
  console.log('Private mode ===>', isPrivate);
});

window chrome the result is error!

@aneudy1702
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aneudy1702 commented Mar 26, 2020 •
edited

This does not seem to work anymore

https://twitter.com/paul_irish/status/1138471166115368960

for desktop you can use

https://mishravikas.com/articles/2019-07/bypassing-anti-incognito-detection-google-chrome.html

(async () => {
  if ("storage" in navigator && "estimate" in navigator.storage) {
    const { usage, quota } = await navigator.storage.estimate();
    console.log(`Using ${usage} out of ${quota} bytes.`);
    if (quota < 120000000) {
      console.log("Incognito");
    } else {
      console.log("Not Incognito");
    }
  } else {
    console.log("Can not detect");
  }
})();

@esemeniuc
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Incorrect reading for Chrome 81 when not in incognito

@mritgupta
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mritgupta commented Sep 14, 2020 •
edited

It's able to detect private mode in chrome 85

@kuldeepchopradotnet
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not working with latest version

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