simple javascript fingerprint

fingerprint.js

var fingerprint = (function(window, screen, navigator) {

    function checksum(str) {
        var hash = 5381,
            i = str.length;
    
        while (i--) hash = (hash * 33) ^ str.charCodeAt(i);
    
        return hash >>> 0;
    }

    function map(arr, fn){
        var i = 0, len = arr.length, ret = [];
        while(i < len){
            ret[i] = fn(arr[i++]);
        }
        return ret;
    }

    return checksum([
        navigator.userAgent,
        [screen.height, screen.width, screen.colorDepth].join('x'),
        new Date().getTimezoneOffset(),
        !!window.sessionStorage,
        !!window.localStorage,
        map(navigator.plugins, function (plugin) {
            return [
                plugin.name,
                plugin.description,
                map(plugin, function (mime) {
                    return [mime.type, mime.suffixes].join('~');
                }).join(',')
            ].join("::");
        }).join(';')
    ].join('###'));

}(this, screen, navigator));

document.body.innerHTML = fingerprint;