Question

如何求解未被发现的typeerror-无法阅读null的属性“ addeventListener”

2019-09-11

105

javascript html css

每当我点击汉堡元素时，什么都没有发生

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <script src="GNG.js"></script>
    <link rel="stylesheet" href="stylesheet/style.css">
    <title>GnG</title>
</head>
<body>
    <nav>
        <div class="navbar-brand">
            George n George
        </div>
        <!-- <a class="navbar-brand" href="#"></a> -->
        <ul class="nav-links">
            <li class= "nav-active"  ><a href="#">Home </a></li>
            <li ><a href="#">Contact</a> </li>
            <li ><a href="#">About us</a></li>
            <li ><a href="#">Laundry</a></li>
            <li ><a href="#">Clothes </a></li>
            <li ><a href="#">Business</a></li>
        </ul>
        <div class="burger">
            <div class="_line1"></div>
            <div class="_line2"></div>
            <div class="_line3"></div>
        </div>
    </nav>

</body>
</html>

我的 css 文件

/*======================== styling the navbaar==========================*/
.burger div{
    width: 25px;
    height: 1px;
    background-color: whitesmoke;
    margin: 5px;
}

.burger{
    display: none;
    cursor: pointer;
}
@media screen and (max-width: 1024px){
    .nav-links{
        width: 40%
    }
}


@media screen and (max-width: 600px){
     body{
    overflow-x: hidden;
    }
    .nav-links{
    position: absolute;
    right: 0px;
    height: 92vh;
    top: 8vh;
    background-color: rgb(21, 19, 43);
    display: flex;
    flex-direction: column;
    align-items: center;
    width: 70%;
    transform: translateX(100%);
    transition: transform 0.9s ease-in;

    }
    .nav-links li{
        opacity: 0;
    }
    .burger{
        display: block;
    }
}
.nav-active{
    transform: translateX(0%)
}
 @keyframes _navLinkFade{
    from{
        opacity: 0;
        transform: translateX(50px)
    }
    to{
        opacity: 1;
        transform: translateX(0px)
    }
}
/* ======================== navbar end==================================*/

和 javascript

const navSlide = () => {
    const burger = document.querySelector('.burger');
    const nav = document.querySelector('.nav-links');
    // const navLinks = document.querySelectorAll('.nav-links li');

    burger.addEventListener('click', () =>
    {
        nav.classList.toggle('nav-active');
        navLinks.forEach((link, index) =>
        {
            link.style.animations = `navLinkFade 0.5s ease forward ${ index / 7 + 1.5 }s`;


        });
    });
}
navSlide();

每当我点击汉堡元素时，菜单应该从右侧淡入，但查看控制台时，我发现 addEventListener 不起作用。尝试使用 addeventListner 的其他项目并得到同样的错误。以为我的浏览器需要更新，我这样做了但无济于事

Answer 1

在关闭 </body> 标签之前移动您的脚本标签或在 DOMContentLoaded 事件之后调用您的函数；

const navSlide = () => {
  const burger = document.querySelector(".burger");
  const nav = document.querySelector(".nav-links");
  // const navLinks = document.querySelectorAll('.nav-links li');

  burger.addEventListener("click", () => {
    nav.classList.toggle("nav-active");
    navLinks.forEach((link, index) => {
      link.style.animations = `navLinkFade 0.5s ease forward ${index / 7 +
        1.5}s`;
    });
  });
};

document.addEventListener("DOMContentLoaded", navSlide);