我基于最新的(v2.0.2) Bootstrap框架创建了一个纯悬停下拉菜单，它支持多个子菜单，我认为我应该发布给未来的用户:

body { padding-top: 60px; padding-bottom: 40px; } .sidebar-nav { padding: 9px 0; } .dropdown-menu .sub-menu { left: 100%; position: absolute; top: 0; visibility: hidden; margin-top: -1px; } .dropdown-menu li:hover .sub-menu { visibility: visible; } .dropdown:hover .dropdown-menu { display: block; } .nav-tabs .dropdown-menu, .nav-pills .dropdown-menu, .navbar .dropdown-menu { margin-top: 0; } .navbar .sub-menu:before { border-bottom: 7px solid transparent; border-left: none; border-right: 7px solid rgba(0, 0, 0, 0.2); border-top: 7px solid transparent; left: -7px; top: 10px; } .navbar .sub-menu:after { border-top: 6px solid transparent; border-left: none; border-right: 6px solid #fff; border-bottom: 6px solid transparent; left: 10px; top: 11px; left: -6px; } <link href="https://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/2.3.2/css/bootstrap.min.css" rel="stylesheet" /> <div class="navbar navbar-fixed-top"> <div class="navbar-inner"> <div class="container-fluid"> <a data-target=".nav-collapse" data-toggle="collapse" class="btn btn-navbar"> <span class="icon-bar"></span> <span class="icon-bar"></span> <span class="icon-bar"></span> </a> <a href="#" class="brand">Project name</a> <div class="nav-collapse"> <ul class="nav"> <li class="active"><a href="#">Home</a></li> <li><a href="#">Link</a></li> <li><a href="#">Link</a></li> <li><a href="#">Link</a></li> <li class="dropdown"> <a data-toggle="dropdown" class="dropdown-toggle" href="#">Dropdown <b class="caret"></b></a> <ul class="dropdown-menu"> <li> <a href="#">2-level Dropdown <i class="icon-arrow-right"></i></a> <ul class="dropdown-menu sub-menu"> <li><a href="#">Action</a></li> <li><a href="#">Another action</a></li> <li><a href="#">Something else here</a></li> <li class="divider"></li> <li class="nav-header">Nav header</li> <li><a href="#">Separated link</a></li> <li><a href="#">One more separated link</a></li> </ul> </li> <li><a href="#">Another action</a></li> <li><a href="#">Something else here</a></li> <li class="divider"></li> <li class="nav-header">Nav header</li> <li><a href="#">Separated link</a></li> <li><a href="#">One more separated link</a></li> </ul> </li> </ul> <form action="" class="navbar-search pull-left"> <input type="text" placeholder="Search" class="search-query span2"> </form> <ul class="nav pull-right"> <li><a href="#">Link</a></li> <li class="divider-vertical"></li> <li class="dropdown"> <a class="#" href="#">Menu</a> </li> </ul> </div> <!-- /.nav-collapse --> </div> </div> </div> <hr> <ul class="nav nav-pills"> <li class="active"><a href="#">Regular link</a></li> <li class="dropdown"> <a href="#" data-toggle="dropdown" class="dropdown-toggle">Dropdown <b class="caret"></b></a> <ul class="dropdown-menu" id="menu1"> <li> <a href="#">2-level Menu <i class="icon-arrow-right"></i></a> <ul class="dropdown-menu sub-menu"> <li><a href="#">Action</a></li> <li><a href="#">Another action</a></li> <li><a href="#">Something else here</a></li> <li class="divider"></li> <li class="nav-header">Nav header</li> <li><a href="#">Separated link</a></li> <li><a href="#">One more separated link</a></li> </ul> </li> <li><a href="#">Another action</a></li> <li><a href="#">Something else here</a></li> <li class="divider"></li> <li><a href="#">Separated link</a></li> </ul> </li> <li class="dropdown"> <a href="#">Menu</a> </li> <li class="dropdown"> <a href="#">Menu</a> </li> </ul>

Demo

用这个脚本覆盖bootstrap.js。

jQuery(document).ready(function ($) {
$('.navbar .dropdown').hover(function() {
    $(this).addClass('extra-nav-class').find('.dropdown-menu').first().stop(true, true).delay(250).slideDown();
}, function() {
    var na = $(this)
    na.find('.dropdown-menu').first().stop(true, true).delay(100).slideUp('fast', function(){ na.removeClass('extra-nav-class') })
});

$('.dropdown-submenu').hover(function() {
    $(this).addClass('extra-nav-class').find('.dropdown-menu').first().stop(true, true).delay(250).slideDown();
}, function() {
    var na = $(this)
    na.find('.dropdown-menu').first().stop(true, true).delay(100).slideUp('fast', function(){ na.removeClass('extra-nav-class') })
});

}); 

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
  }
}

只需三行代码自定义您的CSS样式

.dropdown:hover .dropdown-menu {
   display: block;
}

最好的方法是用鼠标悬停来触发Bootstrap的点击事件。这样，它应该仍然保持触摸设备友好。

$('.dropdown').hover(function(){ 
  $('.dropdown-toggle', this).trigger('click'); 
});