javascript - 将随机字母显示为属性值而不是数组项

Question

所以我试图用 javascript 生成一个注册框，我一直设法这样做，直到我偶然发现了一个奇怪的错误。该脚本在 HTML 中输出:

<input type="f" name="i" alt="r" placeholder="s">

代替:

<input type="email" name="regemail" alt="email" placeholder="What's your email?">

其他 2 个输入也是如此。为什么会这样？我试图寻找任何错误，但控制台没有给我任何错误，我也找不到我编写的代码有任何问题。感谢您的帮助。

var firstInput = ["email", "regemail", "email", "What's your email?"];
    var secondInput = ["password", "regpassword", "password", "Choose a password"];
    var thirdInput = ["password", "confirmpassword", "confirmpassword", "Confirm password"];
    var types = ["type", "name", "alt", "placeholder"];
    var inputNumber = ["firstInput", "secondInput", "thirdInput"];
    var container = document.getElementById('usp-container');

    function register() {

    var div = document.createElement('div');
    div.setAttribute('id', "register-popup");
    container.appendChild(div);
    
    var form = document.createElement('form');
    form.setAttribute('method', "post");
    form.setAttribute('action', "processregistration.php");
    div.appendChild(form);
    
    
        for (i = 0; i < 3; i++) {
            
        function makeInputs(inputs) {
            
        var tableRow = document.createElement('tr');
        form.appendChild(tableRow);
        var tableData = document.createElement('td');
        tableRow.appendChild(tableData);
        var input = document.createElement('input');
        
        for (j = 0; j < 4; j++) {
            
            input.setAttribute(types[j], inputs[j]);
        }
            
        tableData.appendChild(input);
        
        }
            
        makeInputs(inputNumber[i]);
    }
    
    }

    register();

Answer 1

变量名在一个数组中

var firstInput = ["email", "regemail", "email", "What's your email?"];

var inputNumber = ["firstInput", "secondInput", "thirdInput"];

然后您将遍历这些变量名，并尝试使用

获取该变量的值

inputNumber[0]

这会得到字符串"firstInput"，不是一个数组，所以当你这样做的时候

inputNumber[0][0]

您得到字符 "f"，不是数组中的值 "email"。

要使用字符串来引用变量，您必须使用括号表示法，并且在全局范围内看起来像

window[inputNumber[0]][0];

这确实不是一个很好的获取变量的方法

FIDDLE

你最好有一个对象

var values = {
    firstInput  : ["email", "regemail", "email", "What's your email?"],
    secondInput : ["password", "regpassword", "password", "Choose a password"],
    thirdInput  : ["password", "confirmpassword", "confirmpassword", "Confirm password"]
}

然后用键名引用数组

values[inputNumber[0]][0]

FIDDLE