我想有我的引导菜单自动下拉悬停，而不是必须点击菜单标题。我还想去掉菜单标题旁边的小箭头。
当前回答
<!DOCTYPE html> <html> <head> <style> .dropbtn { background-color: #4CAF50; color: white; padding: 16px; font-size: 16px; border: none; cursor: pointer; } .dropdown { position: relative; display: inline-block; } .dropdown-content { display: none; position: absolute; background-color: #f9f9f9; min-width: 160px; 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-content a:hover {background-color: #f1f1f1} .dropdown:hover .dropdown-content { display: block; } .dropdown:hover .dropbtn { background-color: #3e8e41; } </style> </head> <body> <h2>Hoverable Dropdown</h2> <p>Move the mouse over the button to open the dropdown menu.</p> <div class="dropdown"> <button class="dropbtn">Dropdown</button> <div class="dropdown-content"> <a href="#">Link 1</a> <a href="#">Link 2</a> <a href="#">Link 3</a> </div> </div> </body> </html>
其他回答
你可以使用默认的$().dropdown('toggle')方法来切换悬停时的下拉菜单:
$(".nav .dropdown").hover(function() {
$(this).find(".dropdown-toggle").dropdown("toggle");
});
为了加强Sudharshan的回答，我将其包装在一个媒体查询中，以防止在XS显示宽度上出现悬停……
@media (min-width:768px)
{
ul.nav li.dropdown:hover > ul.dropdown-menu {
display: block;
}
.nav .dropdown-menu {
margin-top: 0;
}
}
标记中的插入符号也不是必需的，只是li的下拉类。
我已经发布了一个Bootstrap 3下拉悬停功能的插件，在这个插件中，你甚至可以定义点击下拉切换元素时发生的事情(点击可以被禁用):
https://github.com/istvan-ujjmeszaros/bootstrap-dropdown-hover
既然已经有很多解了，我为什么要做这个?
我对所有之前存在的解决方案都有问题。简单的CSS没有在.dropdown上使用.open类，所以当下拉可见时，下拉切换元素上没有反馈。
js的那些干扰点击.dropdown-toggle，所以下拉菜单显示在悬停，然后隐藏它时，点击一个打开的下拉菜单，移动鼠标将触发下拉菜单再次显示。一些js解决方案破坏了iOS的兼容性，一些插件不能在支持触摸事件的现代桌面浏览器上工作。
这就是为什么我只使用标准的Bootstrap javascript API来防止所有这些问题的Bootstrap下拉悬停插件，没有任何hack。甚至Aria属性在这个插件中也工作得很好。
引导版本4和5解决方案。(兼容)
这些都是使用mouseover和mouseleave事件和一些屏幕宽度检查的完整解决方案。这比纯CSS解决方案更好。
Bootstrap v5 -纯JS(用于webpack)
export class BootstrapOpenMenuHover {
/**
* Constructor.
*/
constructor() {
this.windowWidth = window.innerWidth;
this.mobileBreakPoint = 991; // Put your menu break point here, when it switches to a hamburger icon.
this.dropdownNavItems = document.querySelectorAll(".dropdown-toggle.nav-link");
this.dropdownMenuItems = document.querySelectorAll(".dropdown-menu");
this.setEventListeners();
}
/**
* Set all of our event listeners.
*/
setEventListeners() {
const _self = this;
// To be safe set the width once the dom is loaded.
window.addEventListener('load', function () {
_self.windowWidth = window.innerWidth;
});
// Keep track of the width in the event of a resize.
window.addEventListener('resize', function () {
_self.windowWidth = window.innerWidth;
});
// Bind our hover events.
if (_self.dropdownNavItems !== null) {
for (let i = 0; i < _self.dropdownNavItems.length; i++) {
// On mouse enter.
_self.dropdownNavItems[i].addEventListener('mouseenter', function () {
if (_self.windowWidth >= _self.mobileBreakPoint) {
this.classList.add('show');
this.ariaExpanded = true;
this.dataset.bsToggle = null;
// Update the .dropdown-menu
this.nextElementSibling.classList.add('show');
this.nextElementSibling.dataset.bsPopper = 'none';
}
});
// On mouse leave.
_self.dropdownNavItems[i].addEventListener('mouseleave', function () {
if (_self.windowWidth >= _self.mobileBreakPoint) {
this.classList.remove('show');
this.ariaExpanded = false;
this.dataset.bsToggle = 'dropdown';
// Update the .dropdown-menu
this.nextElementSibling.classList.remove('show');
this.nextElementSibling.dataset.bsPopper = null;
}
});
}
}
// Bind events to .dropdown-menu items.
if (_self.dropdownMenuItems !== null) {
for (let i = 0; i < _self.dropdownMenuItems.length; i++) {
// On mouse enter.
_self.dropdownMenuItems[i].addEventListener('mouseenter', function () {
if (_self.windowWidth >= _self.mobileBreakPoint) {
this.classList.add('show');
this.dataset.bsPopper = 'none';
// Update the .dropdown-toggle
this.previousElementSibling.classList.add('show');
this.previousElementSibling.ariaExpanded = true;
this.previousElementSibling.dataset.bsToggle = null;
}
});
// On mouse leave.
_self.dropdownMenuItems[i].addEventListener('mouseleave', function () {
if (_self.windowWidth >= _self.mobileBreakPoint) {
this.classList.remove('show');
this.dataset.bsPopper = null;
// Update the .dropdown-toggle
this.previousElementSibling.classList.remove('show');
this.previousElementSibling.ariaExpanded = false;
this.previousElementSibling.dataset.bsToggle = 'dropdown';
}
});
}
}
}
}
const bootstrapOpenMenuHover = new BootstrapOpenMenuHover();
Bootstrap v4方案
这将允许您遵循顶级导航链接。
这是基于桌面和移动平台设计的。随意更改BREAK_POINT变量以满足您的需要:D。
jQuery
var WINDOW_WIDTH;
var BREAK_POINT = 991;
(function ($) {
/** Set window width onload */
WINDOW_WIDTH = $(window).width(); // Returns width of browser viewport
/** Set window width if the browser is resized */
$(window).resize(function () {
WINDOW_WIDTH = $(window).width(); // Returns width of browser viewport
});
/** Dropdown menu on mouseenter */
$(".nav-item.dropdown").on('mouseenter', function () {
console.log("mouseenter");
if (WINDOW_WIDTH >= BREAK_POINT) {
// Open up the dropdown
$(this).addClass('show'); // add the class show to the li parent
$(this).children('.nav-link').removeAttr('data-toggle'); // remove the data-toggle attribute so we can click and follow link
$(this).children('.dropdown-menu').addClass('show'); // add the class show to the dropdown div sibling
}
});
/** Dropdown menu on mouseleave */
$(".nav-item.dropdown").on('mouseleave', function () {
console.log("mouseleave");
if (WINDOW_WIDTH >= BREAK_POINT) {
// Close the dropdown
$(this).removeClass('show'); // add the class show to the li parent
$(this).children('.nav-link').attr('data-toggle', 'dropdown'); // remove the data-toggle attribute so we can click and follow link
$(this).children('.dropdown-menu').removeClass('show'); // add the class show to the dropdown div sibling
}
});
});
CSS
@media(min-width: 768px) {
.dropdown-menu {
margin-top: 0; // fixes closing on slow mouse transition
}
}
版本2的解决方案非常简单，只有CSS。 保持相同的友好功能的手机和平板电脑。
@media (min-width: 980px) {
.dropdown:hover .dropdown-menu {
display: block;
}
}
