仅使用 JavaScript 在导航栏外部单击后关闭下拉菜单？

Question

我想制作一个非常简单的下拉菜单，当在导航之外单击时，它会自动隐藏。注意我已经制作了下拉菜单，但是......我不明白如何关闭它。这是我的 HTML 和 javascript 代码。

<section class="dropdownone">
  <div class="container">
    <h1>Dropdown One</h1>
    <li class="MajorDropOne">
      <a href="#">
      <button type="button" 
              class="btn btn-primary dropOnebtn">Click Dropdown</button>
      </a>
      <ul class="dropOne">
        <li>home</li>
        <li>about</li>
        <li>profile</li>
      </ul>
    </li>
  </div>
</section>

Answer 1

使用 JavaScript：

<!DOCTYPE html>
<html>
<head>
<meta name="viewport" content="width=device-width, initial-scale=1">
<style>
.dropbtn {
    background-color: #3498DB;
    color: white;
    padding: 16px;
    font-size: 16px;
    border: none;
    cursor: pointer;
}

.dropbtn:hover, .dropbtn:focus {
    background-color: #2980B9;
}

.dropdown {
    position: relative;
    display: inline-block;
}

.dropdown-content {
    display: none;
    position: absolute;
    background-color: #f1f1f1;
    min-width: 160px;
    overflow: auto;
    box-shadow: 0px 8px 16px 0px rgba(0,0,0,0.2);
    z-index: 1;
}

.dropdown-content a {
    color: black;
    padding: 12px 16px;
    text-decoration: none;
    display: block;
}

.dropdown a:hover {background-color: #ddd;}

.show {display: block;}
</style>
</head>
<body>

<h2>Clickable Dropdown</h2>
<p>Click on the button to open the dropdown menu.</p>

<div class="dropdown">
<button onclick="myFunction()" class="dropbtn">Dropdown</button>
  <div id="myDropdown" class="dropdown-content">
    <a href="#home">Home</a>
    <a href="#about">About</a>
    <a href="#contact">Profile</a>
  </div>
</div>

<script>
/* When the user clicks on the button, 
toggle between hiding and showing the dropdown content */
function myFunction() {
    document.getElementById("myDropdown").classList.toggle("show");
}

// Close the dropdown if the user clicks outside of it
window.onclick = function(event) {
  if (!event.target.matches('.dropbtn')) {

    var dropdowns = document.getElementsByClassName("dropdown-content");
    var i;
    for (i = 0; i < dropdowns.length; i++) {
      var openDropdown = dropdowns[i];
      if (openDropdown.classList.contains('show')) {
        openDropdown.classList.remove('show');
      }
    }
  }
}
</script>

</body>
</html>