jquery.password_strength.js

/*
 * Password Strength (0.1.4)
 * by Sagie Maoz (n0nick.net)
 * n0nick@php.net
 *
 * This plugin will check the value of a password field and evaluate the
 * strength of the typed password. This is done by checking for
 * the diversity of character types: numbers, lowercase and uppercase
 * letters and special characters.
 *
 * Copyright (c) 2010 Sagie Maoz <n0nick@php.net>
 * Licensed under the GPL license, see http://www.gnu.org/licenses/gpl-3.0.html 
 *
 *
 * NOTE: This script requires jQuery to work.  Download jQuery at www.jquery.com
 *
 */

(function($){

var passwordStrength = new function()
{
	this.countRegexp = function(val, rex)
	{
		var match = val.match(rex);
		return match ? match.length : 0;
	};
	
	this.getStrength = function(val, minLength)
	{	
		var len = val.length;
		
		// too short =(
		if (len < minLength)
		{
			return 0;
		}
		
		var nums = this.countRegexp(val, /\d/g),
			lowers = this.countRegexp(val, /[a-z]/g),
			uppers = this.countRegexp(val, /[A-Z]/g),
			specials = len - nums - lowers - uppers;
		
		// just one type of characters =(
		if (nums == len || lowers == len || uppers == len || specials == len)
		{
			return 1;
		}
		
		var strength = 0;
		if (nums)	{ strength+= 2; }
		if (lowers)	{ strength+= uppers? 4 : 3; }
		if (uppers)	{ strength+= lowers? 4 : 3; }
		if (specials) { strength+= 5; }
		if (len > 10) { strength+= 1; }
		
		return strength;
	};
	
	this.getStrengthLevel = function(val, minLength)
	{
		var strength = this.getStrength(val, minLength);

		val = 1;
		if (strength <= 0) {
			val = 1;
		} else if (strength > 0 && strength <= 4) {
			val = 2;
		} else if (strength > 4 && strength <= 8) {
			val = 3;
		} else if (strength > 8 && strength <= 12) {
			val = 4;
		} else if (strength > 12) {
			val = 5;
		}

		return val;
	};
};

$.fn.password_strength = function(options)
{
	var settings = $.extend({
		'container' : null,
		'bar': null, // thanks codemonkeyking
		'minLength' : 6,
		'texts' : {
			1 : 'Too weak',
			2 : 'Weak password',
			3 : 'Normal strength',
			4 : 'Strong password',
			5 : 'Very strong password'
		},
		'onCheck': null
	}, options);
	
	return this.each(function()
	{
		var container = null, $bar = null;
		if (settings.container)
		{
			container = $(settings.container);
		}
		else
		{
			container = $('<span/>').attr('class', 'password_strength');
			$(this).after(container);
		}

		if (settings.bar)
		{
			$bar = $(settings.bar);
		}
		
		$(this).bind('keyup.password_strength', function()
		{
			var val = $(this).val(),
					level = passwordStrength.getStrengthLevel(val, settings.minLength);

			if (val.length > 0)
			{
				var _class = 'password_strength_' + level,
						_barClass = 'password_bar_' + level;
				
				if (!container.hasClass(_class) && level in settings.texts)
				{
					container.text(settings.texts[level]).attr('class', 'password_strength ' + _class);
				}
				if ($bar && !$bar.hasClass(_barClass))
				{
					$bar.attr('class', 'password_bar ' + _barClass);
				}
			}
			else
			{
				container.text('').attr('class', 'password_strength');
				if ($bar) {
					$bar.attr('class', 'password_bar');
				}
			}
			if (settings.onCheck) {
				settings.onCheck.call(this, level);
			}
		});

		if ($(this).val() != '') { // thanks Jason Judge
				$(this).trigger('keyup.password_strength');
		}
	});
};

})(jQuery);