getElementById不返回任何内容或脚本有问题?

问题描述 投票:1回答:2

我正在做一个程序,从输入字段返回值,然后根据条件将字段的字符串改变为x结果。我正在做一个程序,从输入字段返回值,然后根据条件改变字段的字符串和x结果,真的很感谢帮助,因为这里的成员在过去总是极大地帮助我。调试器正在抛出这个错误,当然什么都没有工作。

script.js:22 Uncaught TypeError: Cannot set property 'innerHTML' of null
    at uberChecker (script.js:22)
    at HTMLButtonElement.onclick (index.html:25)

以下是我的代码(初学者):

JS:

    var username = document.getElementById("myUsername").value;
    var groupIs = document.getElementById("myGroup").value;
    var warnings = document.getElementById("myWarning").value;
    var postCount = document.getElementById("myPostCount").value;





 function uberChecker() {

    if ((groupIs != ('Uber' || 'uber') && postCount > '1000') && warnings === '0') {

        document.querySelector("output-box").innerHTML = "You can become Uber !";
    } else if (postCount < '1000' && warnings === '0') {
        document.querySelector("output-box").innerHTML = (username + ' You have ' + postCount + ' posts, you do not meet the requirements');

    } else if (warnings != '0' && postCount > '1000') {
        document.querySelector("output-box").innerHTML = (username + ' You cannot upgrade with ' + warnings + ' warning')
    } else if (postCount < '1000' && warnings != '0') {
        document.querySelector("output-box").innerHTML = (username + ' you have ' + postCount + ' posts which is less than 1000 and you have ' + warnings + '% warning. You cannot upgrade');
    } else {
        document.querySelector("output-box").innerHTML = (username + ' You are already Uber');
    }

 }

HTML:

<!DOCTYPE html>

<html>

<head>
<link rel="stylesheet" type="text/css" href="style.css">

</head>

<body>

<div class="blue-box"></div>

<input type="text" placeholder="Type username" id="myUsername" class="user" >
<input type="text" placeholder="Type user group" id="myGroup" class="group">
<input type="text" placeholder="Type post count" id="myPostCount" class="post">
<input type="text" placeholder="Type warning level" id="myWarning" class="warning">

<div class="UsernameText">Username</div>
<div class="groupText">Group</div>
<div class="postText">Posts</div>
<div class="warningText">Warning</div>


<button type="button" onclick="uberChecker();" class="black-box">Check if you are upgradeable</button>

<div class="output-box">Result will display here</div>

<script src="script.js"></script>

</body>

</html>
javascript html debugging
2个回答
3
投票

在类名前加个点。

document.querySelector(".output-box").innerHTML = "You can become Uber !";

2
投票

问题出在这一行

document.querySelector("output-box").innerHTML

querySelector函数取一个选择器

改成

document.querySelector(".output-box").innerHTML

而且还能用


1
投票

问题在于这些语句。document.querySelector("output-box")

你在这里找的是一个元素而不是一个类。你需要在类名前面加一个点(.),这样querySelector才能正常工作。document.querySelector(".output-box")


0
投票

试试下面的代码,这将消除所有的错误:你的代码有两个问题:

1 - 你在创建输入字段之前声明了变量。

2 - 你使用querySelector的方式不对。

把js放在body标签的最后。

 var username = document.getElementById("myUsername").value;
        var groupIs = document.getElementById("myGroup").value;
        var warnings = document.getElementById("myWarning").value;
        var postCount = document.getElementById("myPostCount").value;





        function uberChecker() {

            if ((groupIs != ('Uber' || 'uber') && postCount > '1000') && warnings === '0') {

                document.querySelector(".output-box").innerHTML = "You can become Uber !";
            } else if (postCount < '1000' && warnings === '0') {
                document.querySelector(".output-box").innerHTML = (username + ' You have ' + postCount + ' posts, you do not meet the requirements');

            } else if (warnings != '0' && postCount > '1000') {
                document.querySelector(".output-box").innerHTML = (username + ' You cannot upgrade with ' + warnings + ' warning')
            } else if (postCount < '1000' && warnings != '0') {
                document.querySelector(".output-box").innerHTML = (username + ' you have ' + postCount + ' posts which is less than 1000 and you have ' + warnings + '% warning. You cannot upgrade');
            } else {
                document.querySelector(".output-box").innerHTML = (username + ' You are already Uber');
            }

        }
<!DOCTYPE html>

<html>

<head>
    <link rel="stylesheet" type="text/css" href="style.css">

</head>

<body>

    <div class="blue-box"></div>

    <input type="text" placeholder="Type username" id="myUsername" class="user">
    <input type="text" placeholder="Type user group" id="myGroup" class="group">
    <input type="text" placeholder="Type post count" id="myPostCount" class="post">
    <input type="text" placeholder="Type warning level" id="myWarning" class="warning">

    <div class="UsernameText">Username</div>
    <div class="groupText">Group</div>
    <div class="postText">Posts</div>
    <div class="warningText">Warning</div>


    <button type="button" onclick="uberChecker();" class="black-box">Check if you are upgradeable</button>

    <div class="output-box">Result will display here</div>
    <script src="script.js"></script>

</body>

</html>

-1
投票

将选择器条件从 ("output-box")(".output-box")

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