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<html xmlns="http://www.w3.org/1999/xhtml">

<head>
    <meta http-equiv="Content-Type" content="text/html; charset=gb2312" />
    <title>
        密碼強度檢測
    </title>
    <style type="text/css">
        body{font:12px/1.5 Arial;} input{float:left;font-size:12px;width:150px;font-family:arial;border:1px
        solid #ccc;padding:3px;} input.correct{border:1px solid green;} input.error{border:1px
        solid red;} #tips{float:left;margin:2px 0 0 20px;} #tips span{float:left;width:50px;height:20px;color:#fff;overflow:hidden;background:#ccc;margin-right:2px;line-height:20px;text-align:center;}
        #tips.s1 .active{background:#f30;} #tips.s2 .active{background:#fc0;} #tips.s3
        .active{background:#cc0;} #tips.s4 .active{background:#090;}
    </style>
    <script type="text/javascript">
        window.onload = function() {
            var oTips = document.getElementById("tips");
            var oInput = document.getElementsByTagName("input")[0];
            var aSpan = oTips.getElementsByTagName("span");
            var aStr = ["弱", "中", "強", "非常好"];
            var i = 0;

            oInput.onkeyup = oInput.onfocus = oInput.onblur = function() {
                var index = checkStrong(this.value);
                this.className = index ? "correct": "error";
                oTips.className = "s" + index;
                for (i = 0; i < aSpan.length; i++) aSpan[i].className = aSpan[i].innerHTML = "";
                index && (aSpan[index - 1].className = "active", aSpan[index - 1].innerHTML = aStr[index - 1])
            }
        };
        /** 強度規(guī)則
            + ------------------------------------------------------- +
            1) 任何少于6個字符的組合，弱；任何字符數(shù)的同類字符組合，弱；
            2) 任何字符數(shù)的兩類字符組合，中；
            3) 12位字符數(shù)以下的三類或四類字符組合，強；
            4) 12位字符數(shù)以上的三類或四類字符組合，非常好。
            + ------------------------------------------------------- +
            **/
        //檢測密碼強度
        function checkStrong(sValue) {
            var modes = 0;
            if (sValue.length < 6) return modes;
            if (/\d/.test(sValue)) modes++; //數(shù)字
            if (/[a-z]/.test(sValue)) modes++; //小寫
            if (/[A-Z]/.test(sValue)) modes++; //大寫  
            if (/\W/.test(sValue)) modes++; //特殊字符
            switch (modes) {
            case 1:
                return 1;
                break;
            case 2:
                return 2;
            case 3:
            case 4:
                return sValue.length < 12 ? 3 : 4
                break;
            }
        }
    </script>
</head>

<body>
    <input type="password" value="" maxlength="16" />
    <div id="tips">
        <span></span>
        <span></span>
        <span></span>
        <span></span>
    </div>
</body>

</html>