未捕获的类型错误：无法在（索引）：72 处读取 null 的属性（读取“addEventListener”）答案

【问题标题】：Uncaught TypeError: Cannot read properties of null (reading 'addEventListener') at (index):72未捕获的类型错误：无法在（索引）：72 处读取 null 的属性（读取“addEventListener”）
【发布时间】：2022-01-20 21:16:44
【问题描述】：

let searchBtn = document.querySelector("#Search-btn");
let searchBar = document.querySelector(".search-bar-container");

searchBtn.addEventListener("click", () => {
  searchBtn.classlist.toggle("fa-times");
  searchBar.classList.toggle("active");
});

let searchBtn = document.querySelector ( '#Search-btn');
let searchBar = document.querySelector ( '.search-bar-container');

searchBtn.addEventListener('click', () =>{

    searchBtn.classlist.toggle('fa-times');
    searchBar.classList.toggle('active');
});

@import url('https://fonts.googleapis.com/css2?family=Nunito:wght@200;300;400;600;700&display=swap');

:root {
    --orange:#ffa500;
    
}

*{
    font-family: 'Nunito', sans-serif;
    margin: 0; padding: 0;
    box-sizing: border-box;
    text-transform: capitalize;
    outline: none; border: none;
    transition: all .2s linear;
    text-decoration: none;
    
}

*::selection{
    background: var(--orange);
    color: #fff;
}

html{
    font-size: 62.5%;
    overflow-x: hidden;
    scroll-padding-top: 6rem;
    scroll-behavior: smooth;
}

header{
    position: fixed;
    top: 0; left: 0; right: 0;
    background: #333;
    z-index: 1000;
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 2rem 9%;
}

header .logo {
    font-size: 2rem;
    font-weight: bolder;
    color: #fff;
    text-transform: uppercase;
}

header .logo span {
    color: var(--orange);
}

header .navbar a{
    font-size: 2rem;
    color: #fff;
    margin:0 .8rem;
}

header .navbar a:hover{
    color: var(--orange);
}

header .icons i{
    font-size: 2.5rem;
    color:#fff;
    cursor: pointer;
    margin-right: 2rem;
}

header .icons i:hover{
    color: var(--orange);
}

header .search-bar-container{
    position: absolute;
    top: 100%; left: 0; right: 0;
    padding: 1.5rem 2rem;
    background: #333;
    border-top: .1rem solid rgba(225, 225, 225, .2);
    display: flex;
    align-items: center;
    z-index: 1001;
    clip-path: polygon(0 0, 100% 0, 0 0);
}

header .search-bar-container.active{
    clip-path: polygon(0 0, 100% 0, 0 0);
}

#search-bar {

    width: 100%;
    padding: 1rem;
    text-transform: none;
    color: #333;
    font-size: 1.7rem;
    border-radius: 100rem;
}

header .search-bar-container label{
    color: #fff;
    cursor: pointer;
    font-size: 3rem;
    margin-left: 1.5rem;
}

header .search-bar-container label:hover {
    color: var(--orange);
}

<!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>Travel Agency</title>
    <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/5.15.4/css/all.min.css">
    <link rel="stylesheet" href="css/style.css">
</head>
<body>
    
<header>
    <a href="#" class="logo"> <span>T</span>ravel</a>

    <nav class="navbar">
        <a href="#home">home</a>
        <a href="#book">book</a>
        <a href="#package">package</a>
        <a href="#services">services</a>
        <a href="#review">review</a>
        <a href="#contact">contact</a>
    </nav>

    <div class="icons">
        <i class="fa fa-search" id="search-btn"></i>
        <i class="fa fa-user" id="login-btn"></i>
    </div>

    <form action="" class="search-bar-container">
        <input type="search" id="search-bar" placeholder="search here...">
        <label for="search-bar" class="fa fa-search" ></label>
    </form>

</header>

当我尝试运行我的 javascript 代码时，它给了我一个错误。我确实检查了我的代码和语法两次我找不到错误请帮助我。

【问题讨论】：

let searchBtn = document.querySelector ( '#Search-btn'); 中的错字。 #Search-btn 应该是 #search-btn
@Robo 的回答应该可以解决这个问题！
如果没有，类似的here

标签： javascript html css compiler-errors

【解决方案1】：

没有什么叫#Search-btn，它是#search-btn。所以，你的 JavaScript 应该是这样的

    let searchBtn = document.querySelector ( '#search-btn');
    let searchBar = document.querySelector ( '.search-bar-container');

    searchBtn.addEventListener('click', () =>{

        searchBtn.classlist.toggle('fa-times');
        searchBar.classList.toggle('active');
    });

接下来，toggle 函数必须用于classList。但是，在这一行：

searchBtn.classlist.toggle('fa-times');

你可以看到你在那里打电话给classlist。修复该问题后，您的 JavaScript 代码应如下所示：

    let searchBtn = document.querySelector ( '#search-btn');
    let searchBar = document.querySelector ( '.search-bar-container');

    searchBtn.addEventListener('click', () => {
        searchBtn.classList.toggle('fa-times', true);
        searchBar.classList.toggle('active', true);
    });

【讨论】：

我做了更改，但代码仍然无法正常工作...
你犯了两个错误；我忘了包括第二个。我已经编辑了答案。现在，当我测试它时，它确实有效。
当我尝试点击搜索图标时，我所做的更改仍然无法正常工作。没有发生任何事情......这也是我的样式表的问题！

【解决方案2】：

你的代码有两个问题，第一个#Search-btnid不存在，应该是#search-btn，第二个searchBtn.classlist.toggle('fa-times');这里classlist不对，应该是classList，如下代码：

let searchBtn = document.querySelector('#search-btn');
let searchBar = document.querySelector('.search-bar-container');

searchBtn.addEventListener('click', () =>{
 searchBtn.classList.toggle('fa-times');
 searchBar.classList.toggle('active');
});

sn-p 下面就是你的sn-p，只修复了上面的两个问题：

let searchBtn = document.querySelector ( '#search-btn');
let searchBar = document.querySelector ( '.search-bar-container');

searchBtn.addEventListener('click', () =>{

    searchBtn.classList.toggle('fa-times');
    searchBar.classList.toggle('active');
});

@import url('https://fonts.googleapis.com/css2?family=Nunito:wght@200;300;400;600;700&display=swap');

:root {
    --orange:#ffa500; 
}

*{
    font-family: 'Nunito', sans-serif;
    margin: 0; padding: 0;
    box-sizing: border-box;
    text-transform: capitalize;
    outline: none; border: none;
    transition: all .2s linear;
    text-decoration: none; 
}

*::selection{
    background: var(--orange);
    color: #fff;
}

html{
    font-size: 62.5%;
    overflow-x: hidden;
    scroll-padding-top: 6rem;
    scroll-behavior: smooth;
}

header{
    position: fixed;
    top: 0; left: 0; right: 0;
    background: #333;
    z-index: 1000;
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 2rem 9%;
}

header .logo {
    font-size: 2rem;
    font-weight: bolder;
    color: #fff;
    text-transform: uppercase;
}

header .logo span {
    color: var(--orange);
}

header .navbar a{
    font-size: 2rem;
    color: #fff;
    margin:0 .8rem;
}

header .navbar a:hover{
    color: var(--orange);
}

header .icons i{
    font-size: 2.5rem;
    color:#fff;
    cursor: pointer;
    margin-right: 2rem;
}

header .icons i:hover{
    color: var(--orange);
}

header .search-bar-container{
    position: absolute;
    top: 100%; left: 0; right: 0;
    padding: 1.5rem 2rem;
    background: #333;
    border-top: .1rem solid rgba(225, 225, 225, .2);
    display: flex;
    align-items: center;
    z-index: 1001;
    clip-path: polygon(0 0, 100% 0, 0 0);
}

header .search-bar-container.active{
    clip-path: inherit;
}

#search-bar {
    width: 100%;
    padding: 1rem;
    text-transform: none;
    color: #333;
    font-size: 1.7rem;
    border-radius: 100rem;
}

<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/5.15.4/css/all.min.css">

<header>
    <a href="#" class="logo"> <span>T</span>ravel</a>

    <nav class="navbar">
        <a href="#home">home</a>
        <a href="#book">book</a>
        <a href="#package">package</a>
        <a href="#services">services</a>
        <a href="#review">review</a>
        <a href="#contact">contact</a>
    </nav>

    <div class="icons">
        <i class="fa fa-search" id="search-btn"></i>
        <i class="fa fa-user" id="login-btn"></i>
    </div>

    <form action="" class="search-bar-container">
        <input type="search" id="search-bar" placeholder="search here...">
        <label for="search-bar" class="fa fa-search" ></label>
    </form>

</header>

【讨论】：

让 searchBtn = document.querySelector ('#search-btn');让 searchBar = document.querySelector ('.search-bar-container'); searchBtn.addEventListener('click', () =>{ searchBtn.classList.toggle('fa-times'); searchBar.classList.toggle('active'); });还是不行
如果你的问题是当你点击搜索图标时看不到input，那是因为你的风格。我刚刚将header .search-bar-container.active{ clip-path: polygon(0 0, 100% 0, 0 0); } 更改为header .search-bar-container.active{ clip-path: inherit;}，您可以通过单击搜索图标查看搜索输入。请看上面我添加的sn-p。
是的，我看到了 sn-p（剪辑路径：继承）但是当我尝试单击搜索图标时，它显示我没有响应......
你看到我的 sn-p 结果了吗？我在问题中看不到对您的 sn-p 的任何编辑。
是的，谢谢问题解决了。