Question

我是HTML5，CSS和Javascript的新学员。如果我的问题非常基本，那么我很抱歉。我正在开发一个响应式导航菜单。当浏览器的宽度大于500时，存在垂直导航栏。一旦屏幕页面的大小小于500（例如在移动电话上），应隐藏水平导航栏，而是显示汉堡包图标。点击汉堡包菜单后，汉堡包图标下方会显示一个垂直导航栏。但问题是当我在导航上调用setAttribute（＆＃34; visibility＆＃34;，＆＃34; visible＆＃34;）或setAttribute（＆＃34; visibility＆＃34;，＆＃34; hidden＆＃34;）时吧，它不起作用。我不知道为什么。 setAttribute被称为屏幕加载时或单击汉堡包图标时。

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta name="X-UA-Compatible" content="ie=edge">
    <link rel="stylesheet" href="./css/normalize.css">
    <link rel="stylesheet" href="./css/page-main.css">
    <link rel="stylesheet" href="./css/master.css">
    <link rel="stylesheet" href="./css/footer.css">
    <!-- fonts -->
    <link href="https://fonts.googleapis.com/css?family=Josefin+Sans:300" rel="stylesheet">

    <!-- fonts -->
  <title>Home Page</title>
  </head>
  <body  onload="hideORShow()">
    <header>

    <nav id="navigation-links" class="navbar navigation-box">
      <div class="col-1of6 nav-item">
        <a class="main-nav-item-page-index" href="./index.html">Home</a>
      </div>

      <div class="col-1of6 nav-item" >
        <a class="main-nav-item-page-index" href="./spring-summer.html">Fall</a>
      </div>

      <div class="col-1of6 nav-item">
        <a class="main-nav-item-page-index" href="./fall-winter.html">Winter</a>
      </div>

      <div class="col-1of6 nav-item">
        <a class="main-nav-item-page-index" href="./leather.html">Leather</a>
      </div>
    </nav>
    <div class="open-slide">
      <a href="#">
        <svg id="hamburgur-icon" onClick="openSlideMenu()">
          <path d="M0,5 30,5" stroke="#000" stroke-width="5"/>
          <path d="M0,14 30,14" stroke="#000" stroke-width="5"/>
          <path d="M0,23 30,23" stroke="#000" stroke-width="5"/>
        </svg>
      </a>
    </div>
    <div id="side-menu" class="side-nav" >
      <a href="#" class="btn-close" onClick="closeSlideMenu()">&times;</a>
      <a class="main-nav-item-page-index" href="./index.html">Home</a>
      <a class="main-nav-item-page-index" href="./spring-summer.html">Fall</a>
      <a class="main-nav-item-page-index" href="./fall-winter.html">Winter</a>
      <a class="main-nav-item-page-index" href="./leather.html">Leather</a>
    </div>
  </header>
  <script type="text/javascript" src="js/main.js"></script>
</body>
</html>

这是我的javascript文件：

var hamburgerMenu = document.getElementById('hamburgur-icon');
var slidingMenu = document.getElementById('side-menu');
var navigationBox = document.getElementById('navigation-links');


function hideORShow(){
  if(width > 500){
    console.log("Inside of hideOrShow function - Window width is greater than 500px, hiding hamburger");
    hamburgerMenu.setAttribute("visibility","hidden");
    slidingMenu.setAttribute("visibility","hidden");
  }
  else{
    console.log("Inside of hideOrShow function - Window width is less than 500px, hiding hamburger");
    navigationBox.setAttribute("visibility","hidden");
    hamburgerMenu.setAttribute("visibility","visible");
  }
}

function openSlideMenu(){
  console.log("hamburger btn clicked");
    slidingMenu.setAttribute("visibility","visible");
    slidingMenu.setAttribute("background-color","red");
}

function closeSlideMenu(){
  console.log("close btn clicked");
    slidingMenu.setAttribute("visibility","hidden");
}

我在chrome调试器中看到在触发事件后可见性属性发生了变化，但我仍然没有在浏览器中看到视觉上的变化。例如，当我单击关闭按钮时，汉堡图标下方的垂直导航栏仍然存在。我会很感激任何提示。

Answer 1

但问题是当我调用setAttribute（＆＃34; visibility＆＃34;，＆＃34; visible＆＃34;）或setAttribute（＆＃34; visibility＆＃34;，＆＃34; hidden＆＃34; ）...

可见性是CSS样式，而不是元素属性。这就是为什么它无法正常工作的原因。尝试替换任何看起来像这样的行：

navigationBox.setAttribute("visibility","hidden");
hamburgerMenu.setAttribute("visibility","visible");

使用：

navigationBox.style.visibility = "hidden";
hamburgerMenu.style.visibility = "visible";

后者实际上为元素设置了visibility CSS样式，而前者在元素上设置了一个属性（作为属性的可见性对它没有任何作用）。

Answer 2

您尝试更改的是CSS样式，而不是HTML属性。有问题的属性是style属性，但在JS中有一个简单的方法：

例如，

slidingMenu.style.visibility = "visible";
slidingMenu.style.backgroundColor = "red";

setAtrribute对标记元素的调用不起作用

2 个答案: