JavaScript验证密码强度_JavaScript

下面的JS代码用于验证密码强度，最强的为100
<!DOCTYPE HTML>
<html>
    <head>
        <title>Password Strength</title>
    </head>
    <script>
    function password_strength(string){
        var h    = 0;
        var size = string.length;
        var result = {};
        string = ('' + string).split('').sort().join('').match(/(.)\1*/g);
        for (i = 0; i != string.length; i += 1) {
         result[string[i].charCodeAt(0)] = string[i].length;
        }
        for(var i in result){
            var p = result[i] / size;
            h -= p * Math.log(p) / Math.log(2);
        }
        var strength = (h / 4) * 100;
        if(strength > 100){
            strength = 100;
        }
        return strength;
    }
    </script>
    <body>
        <p>
            <input type="text" id="password" />
        </p>
        <div style="position: absolute;width: 300px;border:solid 1px;height: 20px;background-color: red;">
            <div style="position: absolute;width: 0;height: 20px;background-color: green;" id="green-bar"></div>
            <span id="str" style="position: absolute;width: 100%;left:0;right: 0;text-align: center;color: white;font-weight: bold;">0%</span>
        </div>
        <script>
            document.getElementById("password").onkeyup = function(){
                var val = this.value;
                var strength = Math.round(password_strength(val));
                document.getElementById("green-bar").style.width = strength + "%";
                document.getElementById("str").innerText = strength + "%";
            };
        </script>
    </body>
</html>