一 随机数测试

下面的例子中生成了两组随机数

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <script>
        var arr = [];

        for(var i = 0;i < 10;i++){
            arr[i] = Math.floor((Math.random()*10));
        }
        document.write("生成[0,9]的随机数:" + arr + "<br>")

        for(var i = 0;i < 10;i++){
            arr[i] = Math.floor((Math.random()*10) + 10);
        }
        document.write("生成[10,19]的随机数:" + arr + "<br>")

    </script>
</body>
</html>

显示效果如下: 

JS使用随机数生成随机验证码-LMLPHP

 二 生成随机验证码实验

本实例中计算了1,a,A的ASCII码,并实现了ASCII码向字符的转换,最后也最了数组转字符串。

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <script>
        document.write("1的ASCII码是" + '1'.charCodeAt(0) + "<br>")
        document.write("a的ASCII码是" + 'a'.charCodeAt(0) + "<br>")
        document.write("A的ASCII码是" + 'A'.charCodeAt(0) + "<br>")
        var arr = [];
        for(var i = 0;i < 10;i++){
            arr[i] = String(i)
        }
        var len = arr.length
        document.write("len = " + len + "<br>")
        for(var i = 0;i < 26;i++){
            arr[i + len] = String.fromCharCode(i+65)
        }
        document.write(arr + "<br>")
        len = arr.length
        document.write("len = " + len + "<br>")
        for(var i = 0;i < 26;i++){
            arr[i + len] = String.fromCharCode(i+97)
        }
        document.write(arr + "<br>")
        //数组转字符串
        var new_str = arr.join("")
        document.write(new_str + "<br>" + "长度:" + new_str.length + "<br>")

        var random_num;
        var mycode = []
        for(var j = 0;j < 4;j++){
            random_num = Math.floor(Math.random() * new_str.length)
            mycode[j] = new_str.charAt(random_num);
        }
        document.write("<hr>生成的随机验证码:" + mycode.join("") + "<br>")

    </script>
</body>
</html>

输出结果:

小结 

06-01 05:36