rsg.js

var rsg = rsg || {};

// (function () {
// 	'use strict';
// }());

rsg = (function(){
	'use strict';

	var string_generator = {};

	string_generator.generateString = function () {
		var availableCharacters = '',
			newString           = '',
			stringLower         = 'abcdefghijklmnopqrstuvwxyz0123456789',
			stringUpper         = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789',
			stringSpecial       = '!@$%^&?',
			stringDefault       = 12,
			characterArray      = [],
			chkLower            = document.getElementById('chk-alpha-lower'),
			chkUpper            = document.getElementById('chk-alpha-upper'),
			chkSpecial          = document.getElementById('chk-special-characters'),
			stringLength        = document.getElementById('txt-string-length').value,
			stringResult        = document.getElementById('txt-result');

		// If nothing is checked, prompt the user to check something
		if (!chkLower.checked && !chkUpper.checked && !chkSpecial.checked) {
			alert('Please select at least one option');
			return false;
		}

		// If lowercase characters are allowed, push them to the characterArray
		if (chkLower.checked) {
			characterArray.push(stringLower);
		}

		// If uppercase characters are allowed, push them to the characterArray
		if (chkUpper.checked) {
			characterArray.push(stringUpper);
		}

		// If special characters are allowed, push them to the characterArray
		if (chkSpecial.checked) {
			characterArray.push(stringSpecial);
		}

		// If no string length is entered, set a default
		if (stringLength === '') {
			stringLength = stringDefault;
		} else {
			parseInt(stringLength);
		}

		// Convert characterArray to a string and set availableCharacters
		availableCharacters = characterArray.toString();

		// While the length of the new string is less than the desired length, add a random character from the availableCharacters
		do {
			var wildcard = Math.random() * (stringLength - 1);
			newString += availableCharacters.substring((wildcard - 1), wildcard);
		} while (newString.length < (stringLength));

		stringResult.value = newString;

		console.log(availableCharacters);
	};

	string_generator.init = function () {
		var submitButton = document.getElementById('btn-submit');
		submitButton.onclick = function (e) {
			e.preventDefault();
			string_generator.generateString();
		};
	};

	return string_generator;

}());

(function(){
	rsg.init();
}());