JavaScript201708/FREE/WEEK2/FREE5/3-code.html at master · yincf/JavaScript201708 · GitHub

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<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">
    <title>验证码</title>
    <style>
        * {
            margin: 0;
            padding: 0;
        }

        .codeBox {
            margin: 20px auto;
            width: 100px;
            height: 35px;
            line-height: 35px;
            font-size: 18px;
            background: lightcoral;
            text-align: center;
            cursor: pointer;
        }
    </style>
</head>
<body>
<div class="codeBox" id="codeBox"></div>

<script>
    var codeBox = document.getElementById('codeBox');
    var codeArea = '0123456789qwertyuiopasdfghjklzxcvbnmQWERTYUIOPASDFGHJKLZXCVBNM';

    /*
     * 思路三：康晶
     *   我每一次把获取的随机索引存储起来，下一次获取最新的索引，看一下是否和之前的索引重复，如果重复，就从新在获取一个索引
     */

    //    function queryRandomCode() {
    //        var ary = [];
    //        var result = '';
    //        while (result.length < 4) {
    //            var ran = Math.round(Math.random() * 61);
    //            if (ary.indexOf(ran) === -1) {
    //                ary.push(ran);
    //                result += codeArea[ran];
    //            }
    //        }
    //        codeBox.innerHTML = result;
    //    }

    var ary = [];
    function queryDistinctRan() {
        var ran = Math.round(Math.random() * 61);
//        while (ary.indexOf(ran) !== -1) {
//            ran = Math.round(Math.random() * 61)
//        }
        for (var i = 0; i < ary.length; i++) {
            if (ran === ary[i]) {
                ran = Math.round(Math.random() * 61);
                i--;
            }
        }
        ary.push(ran);
        return ran;
    }

    function queryRandomCode() {
        var result = '';
        for (var i = 0; i < 4; i++) {
            var ran = queryDistinctRan();
            result += codeArea[ran];
        }
        codeBox.innerHTML = result;
    }


    queryRandomCode();
    codeBox.onclick = queryRandomCode;
</script>
</body>
</html>