Question

我无法显示我已经/没有读过DOM的书籍数组

var booksListArray = [
        {
            title: "Always Running",
            author: "Luis J Rodriguez",
            alreadyRead: true
        },
        {
            title: "Hatchet",
            author: "Gary Paulsen",
            alreadyRead: true
        },
        {
            title: "Autobiography of Malcolm X",
            author: "Malcolm X",
            alreadyRead: true
        },
        {
            title: "Che Guevara: A Revolutionary Life",
            author: "Jon Lee Anderson",
            alreadyRead: false
        },
        {
            title: "The Prince",
            author: "Niccolo Machiavelli",
            alreadyRead: false
        }];

    for (i = 0; i < booksListArray; i++) {
        var currentBook = booksListArray[1];
    };


    if (currentBook.alreadyRead == true) {
       document.write("I have already read " + currentBook.title + " by " + currentBook.author);
    } else {
        document.write("You still have to read " + currentBook.title + " by " + currentBook.author);
    }

Answer 1

我想你想做这样的事情：

for (var i = 0; i < booksListArray.length; i++) {
    var currentBook = booksListArray[i];    
    if (currentBook.alreadyRead == true) {
        document.write("I have already read " + currentBook.title + " by " + currentBook.author);
    } else {
        document.write("You still have to read " + currentBook.title + " by " + currentBook.author);
    }
}

您的代码有几个错误/坏处：
- 你太早关闭循环
- 循环的条件不是使用数组的length - 您需要使用i访问currentBook - 使用var或let初始化i变量
- 您应该填充HTML element而不是使用document.write

以下是一个完整的工作示例：

＆＃13;

var booksListArray = [
{
    title: "Always Running",
    author: "Luis J Rodriguez",
    alreadyRead: true
},
{
    title: "Hatchet",
    author: "Gary Paulsen",
    alreadyRead: true
},
{
    title: "Autobiography of Malcolm X",
    author: "Malcolm X",
    alreadyRead: true
},
{
    title: "Che Guevara: A Revolutionary Life",
    author: "Jon Lee Anderson",
    alreadyRead: false
},
{
    title: "The Prince",
    author: "Niccolo Machiavelli",
    alreadyRead: false
}];

var mydiv = document.getElementById('mylist');
for (var i = 0; i < booksListArray.length; i++) {
    var currentBook = booksListArray[i];    
    if (currentBook.alreadyRead == true) {
    	mydiv.innerHTML += "I have already read " + currentBook.title + " by " + currentBook.author + "<br>";
    } else {
    	mydiv.innerHTML += "You still have to read " + currentBook.title + " by " + currentBook.author + "<br>";
    }
}

＆＃13;

<div id="mylist"></div>

＆＃13;

Answer 2

for (var i = 0; i < booksListArray.length; i++) {
    var currentBook = booksListArray[i]; //index should be i    
    if (currentBook.alreadyRead === true) {
        document.write("I have already read " + currentBook.title + " by " + currentBook.author);
    } else {
        document.write("You still have to read " + currentBook.title + " by " + currentBook.author);
    }
};

无法在DOM上显示我的代码

2 个答案: