How to generate a random password using these requirements?

Question

I was able to do this in C# but can't translate it to Javascript. I found this post "Generate random password string with requirements in javascript" but I can't customize this to my requirements:

A password should be at least 8 chracters in length and maximum of 13 characters and must contain at least one character from each of the following string collections:

string specialCharacters = "~!@#$%^&*()_+=-|\\}]{[\"':;?/>.<,";
string numbers = "0123456789";
string smallLetters = "abcdefghijklmnopqrstuvwxyz";
string capitalLetters = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";

Can you please help? Many thanks!

EDIT:

Here's my code in C#. Sorry, it's a bit lengthy:

private string CreateRandomPassword(int passwordLength)
        {
            string specialCharacters = "~!@#$%^&*()_+=-|\\}]{[\"':;?/>.<,";
            string numbers = "0123456789";
            string smallLetters = "abcdefghijklmnopqrstuvwxyz";
            string capitalLetters = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
            string allowedChars = "";

            char[] chars = new char[passwordLength];
            string password = String.Empty;
            Random rd = new Random();

            int ctr = 0;
            int prop = 4;

            if(!_password.ContainsSpecialCharacters && !_password.ContainsNumbers && !_password.ContainsSmallLetters && !_password.ContainsCapitalLetters)
                return String.Empty;

            string sc = "";
            string num = "";
            string sl = "";
            string cl = "";

            if(_password.ContainsSpecialCharacters)
            {
                // Get a special character randomly
                rd = new Random();
                sc = specialCharacters[rd.Next(0, specialCharacters.Length)].ToString();
                allowedChars += specialCharacters;
            }
            else
            {
                prop--;
            }

            if(_password.ContainsNumbers)
            {
                // Get a random number randomly
                rd = new Random();
                num = numbers[rd.Next(0, numbers.Length)].ToString();
                allowedChars += numbers;
            }
            else
            {
                prop--;
            }

            if(_password.ContainsSmallLetters)
            {
                // Get a small letter randomly
                rd = new Random();
                sl = smallLetters[rd.Next(0, smallLetters.Length)].ToString();
                allowedChars += smallLetters;
            }
            else
            {
                prop--;
            }

            if(_password.ContainsCapitalLetters)
            {
                // Get a capital letter randomly
                rd = new Random();
                cl = capitalLetters[rd.Next(0, capitalLetters.Length)].ToString();
                allowedChars += capitalLetters;

            }
            else
            {
                prop--;
            }

            for (; ctr < passwordLength - prop; ctr++)
                password += allowedChars[rd.Next(0, allowedChars.Length)];


            return password + sc + num + sl + cl;
        }

Answer 1

To check whether it contains a character from either string, you can use Javascript Regular Expressions. Just match your password candidate to those characters as per the link. You are going to try for four matches. The length of the string, you can check in its length property.

Answer 2

Here is what I came up with.

Just run it in the JavaScript console.

(function() {
    var passwd, classTypes, classCount, len, chars, classIndex, charIndex;
    do {
        passwd = "";
        classTypes = [];
        classCount = 0;
        len = Math.round(Math.random() * 5 + 8);
        chars = ["~!@#$%^&*()_+=-|\\}]{[\"':;?/>.<,", "0123456789",
            "abcdefghijklmnopqrstuvwxyz", "ABCDEFGHIJKLMNOPQRSTUVWXYZ"];
        while (passwd.length < len) {
            classIndex = Math.round(Math.random() * 3);
            classTypes[classIndex] = true;
            charIndex = Math.round(Math.random()
                * (chars[classIndex].length - 1));
            passwd += chars[classIndex].charAt(charIndex);
        }
        console.log(JSON.stringify(classTypes));
        classCount = classTypes.filter(function(value, index, object) {
            return value === true;
        }).length;
        console.log("classCount = " + classCount);
        console.log("passwd.length = " + passwd.length);
    } while (classCount < 4);
    console.log("generated pasword is \n" + passwd + "\n");
    console.log("but see http://xkcd.com/936/ for a better approach to paswords");
})();

Answer 3

Try

var specialCharacters = "~!@#$%^&*()_+=-|\\}]{[\"':;?/>.<,";
var numbers = "0123456789";
var smallLetters = "abcdefghijklmnopqrstuvwxyz";
var capitalLetters = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";

var srcs = [specialCharacters, numbers, smallLetters, capitalLetters];

function getRandomChar(string){
    var pos = Math.floor(Math.random() * string.length);
    return string.charAt(pos);
}

//+ Jonas Raoni Soares Silva
//@ http://jsfromhell.com/array/shuffle [v1.0]
function shuffle(o){ //v1.0
    for(var j, x, i = o.length; i; j = parseInt(Math.random() * i), x = o[--i], o[i] = o[j], o[j] = x);
    return o;
}
function generate(){
    var len = 8 + Math.floor(Math.random() * 5);

    var array = [];
    array.push(getRandomChar(specialCharacters));
    array.push(getRandomChar(numbers));
    array.push(getRandomChar(smallLetters));
    array.push(getRandomChar(capitalLetters));

    for(var i = 4; i < len; i++){
        var pos = Math.floor(Math.random() * srcs.length);
        array.push(getRandomChar(srcs[pos]));
    }
    return shuffle(array).join('')
}

for(var i = 0; i < 10; i++){
    console.log(generate())
}

Demo: Fiddle