Javascript暴力和密码生成器

Question

我使用Javascript与Jquery编写了以下密码生成器和暴力函数。

    var prg = prg || {

    config: {
        letters: ["a","b","c","d","e","f","g","h","i","j","k","l","m","n","o","p","q","r","s","t","u","v","w","x","y","z"],
        numbers: ["1","2","3","4","5","6","7","8","9","0"],
        pwMinlength: 2,
        pwMaxLength: 4,
        shuffles: 5,
    },

    users: {
        teatime : {
            password: "",
            login: "teatime",
        },
    },

    init: function() {
        prg.users.teatime.password = prg.generatePassword();
        prg.displayPassword();
        window.requestAnimationFrame(prg.bruteForce());
    },

    generatePassword: function(){
        var letters = prg.config.letters.concat(prg.config.numbers);
        var shuffled = prg.shuffle(letters, prg.config.shuffles);
        var used = [];
        var password = "";
        var pwLength = prg.giveRandomInt(prg.config.pwMinlength, prg.config.pwMaxLength);
        for (var i = 0; i < pwLength; i++) {
            var letter = shuffled[prg.giveRandomInt(0, shuffled.length -1)];
            if (used.indexOf(letter) == -1) {
                password += letter;
                used.push(letter);
            } else {
                i = i - 1;
            }
        }
        return password;
    },

    giveRandomInt:function(min, max) {
        return Math.floor(Math.random() * (max - min + 1)) + min;
    },

    shuffle:function(array, repeat){
        for(var i = 0; i < repeat; i++){
            for(var j = 0; j < array.length; j++) {
                var randomInt = prg.giveRandomInt(0, array.length -1);
                temp = array[randomInt];
                array[randomInt] = array[j];
                array[j] = temp;
            }
        }
        return array;
    },

    displayPassword:function(){
        $("div:first").text("Generated Password: " +prg.users.teatime.password);
    },

    // Erhöhe den Buchstaben vor mir nur dann, wenn ich der letzte buchstabe bin oder aber alle hinter mir auch der letzte buchstabe sind!
    // Wenn es nur letzte buchstaben gibt, füge einen hinzu
    bruteForce:function() {
        var letters = prg.config.letters.concat(prg.config.numbers);
        var target = prg.users.teatime.password;
        var passwordArray = [];
        var foundPassword = false;
        var counter = 0;
        var falseGuesses = [];
        for(var i = 0; i < prg.config.pwMinlength; i++) {
            passwordArray[i] = letters[0];
        }

        while(foundPassword == false) {
            for (var i = 0; i < letters.length; i++) {
                passwordArray[passwordArray.length -1] = letters[i];
                foundPassword = checkPassword(passwordArray, target);
                counter ++;
                if(foundPassword) break;
            }
            if (onlyLastLetter(passwordArray)) {
                for(var i = 0; i < passwordArray.length; i++){
                    passwordArray[i] = letters[0];
                }
                passwordArray[passwordArray.length] = letters[0];
            } else {
                for (var i = 0; i < passwordArray.length; i++) {
                    if (passwordArray[i] == letters[letters.length -1]) {
                        var countLastLetters = 0;
                        for(var j = 0; j < passwordArray.length; j++) {
                            if (passwordArray[j] == letters[letters.length -1]) {
                                countLastLetters += 1;
                            }
                        }
                        if (passwordArray.length - i <= countLastLetters){
                            var indexOfPreviousLetter = letters.indexOf(passwordArray[i - 1]);
                            if(letters[indexOfPreviousLetter + 1] != undefined) {
                                passwordArray[i - 1] = letters[indexOfPreviousLetter + 1];
                            } else {
                                passwordArray[i - 1] = letters[0];
                            }
                        }
                    }
                }   
            }
        }
        $("#counterDisplayer").text("Counted loops:" + counter);
        $("body").append(falseGuesses);

        function onlyLastLetter(passwordArray) {
            for (var i = 0; i < passwordArray.length; i++) {
                if(passwordArray[i] != letters[letters.length -1]) {
                    return false;
                }
            }
            return true;
        }

        function checkPassword(passwordArray, target) {
            var password = passwordArray.join("");
            if (password != target) {
                falseGuesses[falseGuesses.length] = "No Match: "+password+ "<br>";
                return false;
            } else {
                $("#passwordDisplayer").text("Match: "+password);
                return true;
            }
        }

    },

}

$(document).ready(function() {
    prg.init();
});

此脚本的目标是生成密码，然后用Brute Force猜测并计算尝试次数。

我的问题在于蛮力部分：
它现在很好用，但有没有办法优化这个？导致它在创建这些密码时冻结浏览器：＆lt;

或者我有什么可以做的，所以浏览器不会冻结，我可以看到生成的当前密码和蛮力进展（实际猜到的密码）？