我想创建一个与此类似的下拉代码，但是当我进入页面时“下拉”已经被下拉，所以我不必单击或悬停它， 就像一把已经打开的 Accordion 一样亲切，我希望有人能提供帮助!我不知道还能怎么解释。
我所知道的是，对于我正在尝试编码的东西，我希望它是这样的。 因此，我希望下拉元素已处于事件状态并显示，而不必单击或悬停。
<!DOCTYPE html>
<html>
<head>
<meta name="viewport" content="width=device-width, initial-scale=1">
<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/4.7.0/css/font-awesome.min.css">
<style>
body {
font-family: "Lato", sans-serif;
}
/* Fixed sidenav, full height */
.sidenav {
height: 100%;
width: 200px;
position: fixed;
z-index: 1;
top: 0;
left: 0;
background-color: #111;
overflow-x: hidden;
padding-top: 20px;
}
/* Style the sidenav links and the dropdown button */
.sidenav a, .dropdown-btn {
padding: 6px 8px 6px 16px;
text-decoration: none;
font-size: 20px;
color: #818181;
display: block;
border: none;
background: none;
width: 100%;
text-align: left;
cursor: pointer;
outline: none;
}
/* On mouse-over */
.sidenav a:hover, .dropdown-btn:hover {
color: #f1f1f1;
}
/* Main content */
.main {
margin-left: 200px; /* Same as the width of the sidenav */
font-size: 20px; /* Increased text to enable scrolling */
padding: 0px 10px;
}
/* Add an active class to the active dropdown button */
.active {
background-color: green;
color: white;
}
/* Dropdown container (hidden by default). Optional: add a lighter background color and some left padding to change the design of the dropdown content */
.dropdown-container {
display: none;
background-color: #262626;
padding-left: 8px;
}
/* Optional: Style the caret down icon */
.fa-caret-down {
float: right;
padding-right: 8px;
}
/* Some media queries for responsiveness */
@media screen and (max-height: 450px) {
.sidenav {padding-top: 15px;}
.sidenav a {font-size: 18px;}
}
</style>
</head>
<body>
<div class="sidenav">
<a href="#about">About</a>
<a href="#services">Services</a>
<a href="#clients">Clients</a>
<a href="#contact">Contact</a>
<button class="dropdown-btn">Dropdown
<i class="fa fa-caret-down"></i>
</button>
<div class="dropdown-container">
<a href="#">Link 1</a>
<a href="#">Link 2</a>
<a href="#">Link 3</a>
</div>
<a href="#contact">Search</a>
</div>
<div class="main">
<h2>Sidebar Dropdown</h2>
<p>Click on the dropdown button to open the dropdown menu inside the side navigation.</p>
<p>This sidebar is of full height (100%) and always shown.</p>
<p>Some random text..</p>
</div>
<script>
/* Loop through all dropdown buttons to toggle between hiding and showing its dropdown content - This allows the user to have multiple dropdowns without any conflict */
var dropdown = document.getElementsByClassName("dropdown-btn");
var i;
for (i = 0; i < dropdown.length; i++) {
dropdown[i].addEventListener("click", function() {
this.classList.toggle("active");
var dropdownContent = this.nextElementSibling;
if (dropdownContent.style.display === "block") {
dropdownContent.style.display = "none";
} else {
dropdownContent.style.display = "block";
}
});
}
</script>
</body>
</html> 最佳答案
.dropdown-container {
display: block;
background-color: #262626;
padding-left: 8px;
}
将 display: none; 替换为 display: block;
这是结果
/* Loop through all dropdown buttons to toggle between hiding and showing its dropdown content - This allows the user to have multiple dropdowns without any conflict */
var dropdown = document.getElementsByClassName("dropdown-btn");
var i;
for (i = 0; i < dropdown.length; i++) {
dropdown[i].addEventListener("click", function() {
this.classList.toggle("active");
var dropdownContent = this.nextElementSibling;
if (dropdownContent.style.display === "block") {
dropdownContent.style.display = "none";
} else {
dropdownContent.style.display = "block";
}
});
}body {
font-family: "Lato", sans-serif;
}
/* Fixed sidenav, full height */
.sidenav {
height: 100%;
width: 200px;
position: fixed;
z-index: 1;
top: 0;
left: 0;
background-color: #111;
overflow-x: hidden;
padding-top: 20px;
}
/* Style the sidenav links and the dropdown button */
.sidenav a, .dropdown-btn {
padding: 6px 8px 6px 16px;
text-decoration: none;
font-size: 20px;
color: #818181;
display: block;
border: none;
background: none;
width: 100%;
text-align: left;
cursor: pointer;
outline: none;
}
/* On mouse-over */
.sidenav a:hover, .dropdown-btn:hover {
color: #f1f1f1;
}
/* Main content */
.main {
margin-left: 200px; /* Same as the width of the sidenav */
font-size: 20px; /* Increased text to enable scrolling */
padding: 0px 10px;
}
/* Add an active class to the active dropdown button */
.active {
background-color: green;
color: white;
}
/* Dropdown container (hidden by default). Optional: add a lighter background color and some left padding to change the design of the dropdown content */
.dropdown-container {
display: block;
background-color: #262626;
padding-left: 8px;
}
/* Optional: Style the caret down icon */
.fa-caret-down {
float: right;
padding-right: 8px;
}
/* Some media queries for responsiveness */
@media screen and (max-height: 450px) {
.sidenav {padding-top: 15px;}
.sidenav a {font-size: 18px;}
}<meta name="viewport" content="width=device-width, initial-scale=1">
<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/4.7.0/css/font-awesome.min.css">
<div class="sidenav">
<a href="#about">About</a>
<a href="#services">Services</a>
<a href="#clients">Clients</a>
<a href="#contact">Contact</a>
<button class="dropdown-btn">Dropdown
<i class="fa fa-caret-down"></i>
</button>
<div class="dropdown-container">
<a href="#">Link 1</a>
<a href="#">Link 2</a>
<a href="#">Link 3</a>
</div>
<a href="#contact">Search</a>
</div>
<div class="main">
<h2>Sidebar Dropdown</h2>
<p>Click on the dropdown button to open the dropdown menu inside the side navigation.</p>
<p>This sidebar is of full height (100%) and always shown.</p>
<p>Some random text..</p>
</div>关于javascript - 如何保持下拉菜单处于事件状态，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/51149021/