关于可点击的下拉菜单 [英] About clickable dropdown menu
本文介绍了关于可点击的下拉菜单的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我遵循这个链接，试图点击下拉菜单
I follow this link to try to make a clickable dropdown menu.
我注意到链接中的代码是一个下拉菜单，我认为这段代码是用于创建下拉菜单。
I notice the code from the link is for one dropdown menu and I think this code is for create the dropdown menu.
<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">Contact</a>
</div>
</div>
我尝试创建另外两个下拉菜单，所以我复制上面的代码两次
I try to create another two dropdown menus so I copy the code above twice
2nd dropdown
<div class="dropdown">
<button onclick="myFunction()" class="dropbtn">Dropdown2</button>
<div id="myDropdown" class="dropdown-content">
<a href="#home">Home2</a>
<a href="#about">About2</a>
<a href="#contact">Contact2</a>
</div>
</div>
3rd dropdown
<div class="dropdown">
<button onclick="myFunction()" class="dropbtn">Dropdown3</button>
<div id="myDropdown" class="dropdown-content">
<a href="#home">Home2</a>
<a href="#about">About2</a>
<a href="#contact">Contact2</a>
不要编辑标签和标签内的任何内容，所以我点击运行链接查看结果。
I don't edit anything inside the tag and tag so I click Run on link to see the result.
只有第一个下拉菜单（原来的）可以显示菜单，另外两个下拉菜单不显示任何内容。
Only the first dropdown menu (the original one) can show the menu, the other two dropdown menu do not show anything.
我猜原因是第二个下拉菜单，第三个下拉菜单里面没有适当的内容。
所以我开始修改代码并标记。
I guess the reason is the second dropdown menu and the third dropdown menu do not have proper content inside the and tag. So I start to modify the code in and tag.
这是我为第二个下拉列表和第三个下拉菜单添加的完整代码。 p>
Here is the full code the I added for the second dropdown and the third dropdown menu.
<!DOCTYPE html>
<html>
<head>
<style>
/*1st dropdown*/
.dropbtn {
background-color: #4CAF50;
color: white;
padding: 16px;
font-size: 16px;
border: none;
cursor: pointer;
}
.dropbtn:hover, .dropbtn:focus {
background-color: #3e8e41;
}
.dropdown {
position: relative;
display: inline-block;
}
.dropdown-content {
display: none;
position: absolute;
background-color: #f9f9f9;
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: #f1f1f1}
.show {display:block;}
/*2nd dropdown*/
.dropbtn2 {
background-color: #4CAF50;
color: white;
padding: 16px;
font-size: 16px;
border: none;
cursor: pointer;
}
.dropbtn2:hover, .dropbtn2:focus {
background-color: #3e8e41;
}
.dropdown2 {
position: relative;
display: inline-block;
}
.dropdown-content2 {
display: none;
position: absolute;
background-color: #f9f9f9;
min-width: 160px;
overflow: auto;
box-shadow: 0px 8px 16px 0px rgba(0,0,0,0.2);
z-index: 1;
}
.dropdown-content2 a {
color: black;
padding: 12px 16px;
text-decoration: none;
display: block;
}
.dropdown2 a:hover {background-color: #f1f1f1}
.show2 {display:block;}
/*3rd dropdown*/
.dropbtn3 {
background-color: #4CAF50;
color: white;
padding: 16px;
font-size: 16px;
border: none;
cursor: pointer;
}
.dropbtn3:hover, .dropbtn2:focus {
background-color: #3e8e41;
}
.dropdown3 {
position: relative;
display: inline-block;
}
.dropdown-content3 {
display: none;
position: absolute;
background-color: #f9f9f9;
min-width: 160px;
overflow: auto;
box-shadow: 0px 8px 16px 0px rgba(0,0,0,0.2);
z-index: 1;
}
.dropdown-content3 a {
color: black;
padding: 12px 16px;
text-decoration: none;
display: block;
}
.dropdown3 a:hover {background-color: #f1f1f1}
.show3 {display:block;}
</style>
</head>
<body>
<h2>Clickable Dropdown</h2>
<p>Click on the button to open the dropdown menu.</p>
1st dropdown
<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">Contact</a>
</div>
</div>
2nd dropdown
<div class="dropdown2">
<button onclick="myFunction2()" class="dropbtn2">Dropdown2</button>
<div id="myDropdown2" class="dropdown-content2">
<a href="#home">Home2</a>
<a href="#about">About2</a>
<a href="#contact">Contact2</a>
</div>
</div>
3rd dropdown
<div class="dropdown3">
<button onclick="myFunction3()" class="dropbtn3">Dropdown3</button>
<div id="myDropdown3" class="dropdown-content3">
<a href="#home">Home3</a>
<a href="#about">About3</a>
<a href="#contact">Contact3</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');
}
}
}
}
//for 2nd dropdown
function myFunction2() {
document.getElementById("myDropdown2").classList.toggle("show2");
}
// Close the dropdown if the user clicks outside of it
window.onclick = function(event) {
if (!event.target.matches('.dropbtn2')) {
var dropdowns = document.getElementsByClassName("dropdown-content2");
var i;
for (i = 0; i < dropdowns.length; i++) {
var openDropdown = dropdowns[i];
if (openDropdown.classList.contains('show2')) {
openDropdown.classList.remove('show2');
}
}
}
}
//for 3rd dropdown
function myFunction3() {
document.getElementById("myDropdown3").classList.toggle("show3");
}
// Close the dropdown if the user clicks outside of it
window.onclick = function(event) {
if (!event.target.matches('.dropbtn3')) {
var dropdowns = document.getElementsByClassName("dropdown-content3");
var i;
for (i = 0; i < dropdowns.length; i++) {
var openDropdown = dropdowns[i];
if (openDropdown.classList.contains('show3')) {
openDropdown.classList.remove('show3');
}
}
}
}
</script>
</body>
</html>
当我运行代码时，所有按钮都可以在点击时打开下拉菜单。但是，当我点击下拉菜单之外时，只有第三个按钮可以关闭下拉菜单，第一个和第二个按钮仍然打开下拉菜单。
When I run the code, all buttons can open the dropdown menu when clicked. However, when I click outside of the dropdown menus, only the third button can close the dropdown menu, the first and the second button still open the dropdown menu.
这里是我的问题。
- 复制另外两组代码创建另外两个下拉菜单似乎不是一个好习惯，因为代码会变得凌乱好的调试，即使有更新，我已经多次更改代码。
但是，如果不要复制另外两组代码，则其他两个下拉菜单将无法正常工作。
However, if don't copy another two sets of code, the other two dropdown menu will not work.
- 即使我复制另外两套代码来创建另外两个下拉菜单，我不明白下拉菜单不会关闭时鼠标点击它们之外。
感谢您的建议。谢谢。
推荐答案
您正在覆盖三次window.onclick事件功能。只有最后一个功能启动。如果你把这三个函数组合在一起，它可以工作。
You are overriding three times window.onclick event function. Only the last function launches. If you combine the three functions in one, it works.
现在你的代码是：
<!DOCTYPE html>
<html>
<head>
<style>
/*1st dropdown*/
.dropbtn {
background-color: #4CAF50;
color: white;
padding: 16px;
font-size: 16px;
border: none;
cursor: pointer;
}
.dropbtn:hover, .dropbtn:focus {
background-color: #3e8e41;
}
.dropdown {
position: relative;
display: inline-block;
}
.dropdown-content {
display: none;
position: absolute;
background-color: #f9f9f9;
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: #f1f1f1}
.show {display:block;}
/*2nd dropdown*/
.dropbtn2 {
background-color: #4CAF50;
color: white;
padding: 16px;
font-size: 16px;
border: none;
cursor: pointer;
}
.dropbtn2:hover, .dropbtn2:focus {
background-color: #3e8e41;
}
.dropdown2 {
position: relative;
display: inline-block;
}
.dropdown-content2 {
display: none;
position: absolute;
background-color: #f9f9f9;
min-width: 160px;
overflow: auto;
box-shadow: 0px 8px 16px 0px rgba(0,0,0,0.2);
z-index: 1;
}
.dropdown-content2 a {
color: black;
padding: 12px 16px;
text-decoration: none;
display: block;
}
.dropdown2 a:hover {background-color: #f1f1f1}
.show2 {display:block;}
/*3rd dropdown*/
.dropbtn3 {
background-color: #4CAF50;
color: white;
padding: 16px;
font-size: 16px;
border: none;
cursor: pointer;
}
.dropbtn3:hover, .dropbtn2:focus {
background-color: #3e8e41;
}
.dropdown3 {
position: relative;
display: inline-block;
}
.dropdown-content3 {
display: none;
position: absolute;
background-color: #f9f9f9;
min-width: 160px;
overflow: auto;
box-shadow: 0px 8px 16px 0px rgba(0,0,0,0.2);
z-index: 1;
}
.dropdown-content3 a {
color: black;
padding: 12px 16px;
text-decoration: none;
display: block;
}
.dropdown3 a:hover {background-color: #f1f1f1}
.show3 {display:block;}
</style>
</head>
<body>
<h2>Clickable Dropdown</h2>
<p>Click on the button to open the dropdown menu.</p>
1st dropdown
<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">Contact</a>
</div>
</div>
2nd dropdown
<div class="dropdown2">
<button onclick="myFunction2()" class="dropbtn2">Dropdown2</button>
<div id="myDropdown2" class="dropdown-content2">
<a href="#home">Home2</a>
<a href="#about">About2</a>
<a href="#contact">Contact2</a>
</div>
</div>
3rd dropdown
<div class="dropdown3">
<button onclick="myFunction3()" class="dropbtn3">Dropdown3</button>
<div id="myDropdown3" class="dropdown-content3">
<a href="#home">Home3</a>
<a href="#about">About3</a>
<a href="#contact">Contact3</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");
}
//for 2nd dropdown
function myFunction2() {
document.getElementById("myDropdown2").classList.toggle("show2");
}
//for 3rd dropdown
function myFunction3() {
document.getElementById("myDropdown3").classList.toggle("show3");
}
// 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');
}
}
}
if (!event.target.matches('.dropbtn2')) {
var dropdowns = document.getElementsByClassName("dropdown-content2");
var i;
for (i = 0; i < dropdowns.length; i++) {
var openDropdown = dropdowns[i];
if (openDropdown.classList.contains('show2')) {
openDropdown.classList.remove('show2');
}
}
}
if (!event.target.matches('.dropbtn3')) {
var dropdowns = document.getElementsByClassName("dropdown-content3");
var i;
for (i = 0; i < dropdowns.length; i++) {
var openDropdown = dropdowns[i];
if (openDropdown.classList.contains('show3')) {
openDropdown.classList.remove('show3');
}
}
}
}
</script>
</body>
</html>
这篇关于关于可点击的下拉菜单的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
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