imprintjs: A JavaScript repository from mattbrailsford

A javascript library for browser fingerprinting.

Installation

Simply include imprint.min.js in your HTML page. It has no other dependencies.

<script type="text/javascript" src="imprint.min.js"></script>

Usage

To create a fingerprint, instantiate a new instance of the ImprintJs class and call getFingerprint passing in a list of tests you wish to run. The getFingerprint method returns a javascript Promise which once all tests have run, returns the generated fingerprint.

<script type="text/javascript">
    
    var browserTests = [
        "audio",
        "availableScreenResolution",
        "canvas",
        "colorDepth",
        "cookies",
        "cpuClass",
        "deviceDpi",
        "doNotTrack",
        "indexedDb",
        "installedFonts",
        "language",
        "localIp",
        "localStorage",
        "pixelRatio",
        "platform",
        "plugins",
        "processorCores",
        "screenResolution",
        "sessionStorage",
        "timezoneOffset",
        "touchSupport",
        "userAgent",
        "webGl"
    ];

    imprint.test(browserTests).then(function(result){
      console.log(result);
    });

</script>

Supported Tests

Out of the box, ImprintJS comes with the following tests

audio
availableScreenResolution
canvas
colorDepth
cookies
cpuClass
deviceDpi
doNotTrack
indexedDb
installedFonts
installedLanguages [experimental, inconsistent results]
language
localIp
localStorage
mediaDevices [experimental, inconsistent results]
pixelRatio
platform
plugins
processorCores
publicIp [external request]
screenResolution
sessionStorage
timezoneOffset
touchSupport
userAgent
webGl

Custom Tests

If you'd like to add your own custom test, you can register a new test like so

imprint.registerTest("testAlias", function(){
	return new Promise(function(resolve) {
	    var value = ""; // Some code to perform a test
		return resolve(value);
	});
});

All tests must have an alias, and a factory method that creates a javascript Promise that performs the actual test. We use promises to allow for async tests. On completion, the promise should always resolve. If a value cannot be determined, simply resolve with an empty string.

Known issues

Some versions of Firefox for Android report inccorrect screen.height / screen.width values as they subtract the browser chrome when they shouldnt do resulting in inconsistant screenResolution test values. No current workaround. Issue 1120452
Firefox for Android reports a color depth of 24 instead of 32 as they percieve the last 8 bits as being alpha and so shouldn't be concidered as part of the color depth. As a workaround, we treat all 32 bit colorDepths as 24 bit. Issue 424386

Acknowledgement

ImprintJS is based heavily on code from a number of libraries, namely