rankpassword.js

/*javascript rank password function
copyright ryanday 2010
mit/gpl license

feel free to use and include as long as the code retains the above copyright. =)

PURPOSE:
i needed to present users with a password quality visual alert on keyup for the password on a registration form. this is the core function with no depends

USE://jquery example
$(".password-input").bind('keypress',function(){
	var score = rankPassword($(this).val());
	if(score >= 4) {
		alert('strong');
	} else if(score == 3) {
		alert('good');
	} else if(score == 2){
		alert('okay');
	} else {
		alert('weak');
	}
});


*/
var rankPassword = function(pw){
	pw = $.trim(pw);
	var checks = {
		length:function(pw){
			return pw.length >= 6;
		},
		digit:function(pw){
			var l = pw.length;
			var all_alpha = new RegExp("/[a-z]{"+l+","+l+"}/i");
			var all_digit = new RegExp("/[0-9]{"+l+","+l+"}/i");
			return !pw.match(all_alpha) && !pw.match(all_digit); 
		},
		punct:function(pw){
			return pw.match(/[^[a-z0-9]+/i);
		},
		upper:function(pw){
			return pw.toLowerCase() != pw && pw.toUpperCase() != pw
		},
		reallylong:function(pw){
			return pw.length >= 9;
		}
	};
	var score = 0;
	if(checks.length(pw)){
		for( var k in checks){
			score += (checks[k](pw)?1:0);
		}
	}
	return score;
};