JavaScript random password generator

randomPasswordGenerator

<script>
/*Random password generator
Set length to desired password length
Tell it if you want to include letters, capital letters, numbers, and symbols
Tell it if the password MUST require a capital letter, number, or symbol
Drag into browser to generate a password 
*/
var length = 10;

var lettersAllowed = true;
var capitalLettersAllowed = true;
var numbersAllowed = true;
var symbolsAllowed = true;

var mustIncludeCapitalLetter = true;
var mustIncludeNumber = true;
var mustIncludeSymbol = true;

var 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";
var numbers = "1,2,3,4,5,6,7,8,9,0";
var symbols = "!,@,#,$,%,&";

var validChars = "";
var password = "";

var charsChosen = 0;

buildValidChoicesString();
createRandomPasswordString();

function buildValidChoicesString() {
	//Build list of options
	if (lettersAllowed == true) {
		validChars += "," + letters;
	}
	if (capitalLettersAllowed == true) {
		validChars += "," + letters.toUpperCase();
	}
	if (numbersAllowed == true) {
		//added twicec to make numbers more common in the array
		validChars +="," + numbers;
		validChars +="," + numbers;
	} 
	if (symbolsAllowed == true) {
		//added three times to make symbols more common in the array
		validChars +="," + symbols;
		validChars +="," + symbols;
		validChars +="," + symbols;
	}

	console.log("valid chars: " + validChars);
}

function insertRequiredCharacters() {
	var requiredChars = "";
	if (mustIncludeCapitalLetter == true) {
		requiredChars += chooseLetter().toUpperCase();
		charsChosen++;
	}

	if (mustIncludeNumber == true) {
		requiredChars += chooseNumber();
		charsChosen++;
	}

	if (mustIncludeSymbol == true) {
		requiredChars += chooseSymbol();
		charsChosen++;
	}
	return requiredChars;
}

function createRandomPasswordString() {
	//Put in any "must have" characters, like a number or a capital letter
	password = insertRequiredCharacters();
	//Create the rest of the password string
	validCharsArray = validChars.split(",");
	for (charsChosen; charsChosen < length; charsChosen++) {
		var randomChar = validCharsArray[Math.floor(Math.random() * validCharsArray.length)];
		password += randomChar;
	}
	var passwordArray = password.split(""); 
	password = shufflePassword(passwordArray);
}

function shufflePassword(array) {
	//shuffle code from http://stackoverflow.com/questions/2450954/how-to-randomize-shuffle-a-javascript-array
    for (var i = array.length - 1; i > 0; i--) {
        var j = Math.floor(Math.random() * (i + 1));
        var temp = array[i];
        array[i] = array[j];
        array[j] = temp;
    }
    var shuffled = array.toString().replace(/,/g ,"");
    return shuffled;
}

document.write("Random password with " + length + " characters: " + password);


function chooseLetter() {
	var lettersArray = letters.split(",");
	var index = Math.floor(Math.random() * lettersArray.length);
	return lettersArray[index];
}


function chooseSymbol() {
	var symbolsArray = symbols.split(",");
	var index = Math.floor(Math.random() * symbolsArray.length);
	return symbolsArray[index];
}

function chooseNumber() {
	var index = Math.floor(Math.random() * 10);
	return index;
}

</script>