[Bootstrap]Bootstrap中如何使用jQuery实现下拉菜单(dropdown menu)在鼠标悬停时自动下拉展开菜单选项?

Bootstrap 作者: Rector 114 次阅读 · 读完约需 2 分钟 收藏本文

郑重申明:本文未经许可,禁止任何形式转载

问题描述

在前端Bootstrap开发时,有时候会使用到Bootstrap的下拉菜单(dropdown menu),Bootstrap提供的下拉菜单只有在点击时才会下拉展开菜单的选项,那么要实现在鼠标悬停时自动展开菜单选项应该如何处理呢?

方案一

以下是一个没有使用Javascript或者jQuery脚本和纯CSS实现的基于Bootstrap 2.0.2及以上版本的鼠标悬停时下拉菜单自动展开的功能,同时支持多级下拉菜单的自动展开,代码如下:

Style格式:

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;
}

HTML:

<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>

方案二

以下是一个使用jQyery实现的下拉菜单(dropdown menu)悬停时自动展开的功能:

jQuery('ul.nav li.dropdown').hover(function() {
  jQuery(this).find('.dropdown-menu').stop(true, true).delay(200).fadeIn();
}, function() {
  jQuery(this).find('.dropdown-menu').stop(true, true).delay(200).fadeOut();
});

或者:

HTML:

<ul class="list-unstyled list-inline">
    <li class="dropdown">
        <a data-toggle="dropdown" href="#"><i class="fa fa-bars"></i> Dropdown 1</a>
        <ul class="dropdown-menu">
            <li><a href="">Item 1</a></li>
            <li><a href="">Item 2</a></li>
            <li><a href="">Item 3</a></li>
            <li><a href="">Item 4</a></li>
            <li><a href="">Item 5</a></li>
        </ul>
    </li>
    <li class="dropdown">
        <a data-toggle="dropdown" href="#"><i class="fa fa-user"></i> Dropdown 2</a>
        <ul class="dropdown-menu">
            <li><a href="">Item A</a></li>
            <li><a href="">Item B</a></li>
            <li><a href="">Item C</a></li>
            <li><a href="">Item D</a></li>
            <li><a href="">Item E</a></li>
        </ul>
    </li>
</ul>

jQuery:

<script>
    $('.dropdown').hover(
        function() {
            $(this).find('.dropdown-menu').stop(true, true).delay(200).fadeIn();
        },
        function() {
            $(this).find('.dropdown-menu').stop(true, true).delay(200).fadeOut();
        }
    );

    $('.dropdown-menu').hover(
        function() {
            $(this).stop(true, true);
        },
        function() {
            $(this).stop(true, true).delay(200).fadeOut();
        }
    );
</script>

方案三

这个实现方式有些取巧了,即当鼠标在下拉菜单上悬停时,使用jQuery代码触发下拉菜单的点击(click)事件,实现了鼠标悬停时自动展开下拉菜单选项的目的,如下:

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

方案四

封装一个jQuery的下拉菜单悬停展开菜单选项的插件,如下:

;(function($, window, undefined) {
    var $allDropdowns = $();

    $.fn.dropdownHover = function(options) {

        $allDropdowns = $allDropdowns.add(this.parent());

        return this.each(function() {
            var $this = $(this),
                $parent = $this.parent(),
                defaults = {
                    delay: 500,
                    instantlyCloseOthers: true
                },
                data = {
                    delay: $(this).data('delay'),
                    instantlyCloseOthers: $(this).data('close-others')
                },
                settings = $.extend(true, {}, defaults, options, data),
                timeout;

            $parent.hover(function(event) {

                if(!$parent.hasClass('open') && !$this.is(event.target)) {
                    return true;
                }

                if(settings.instantlyCloseOthers === true)
                    $allDropdowns.removeClass('open');

                window.clearTimeout(timeout);
                $parent.addClass('open');
            }, function() {
                timeout = window.setTimeout(function() {
                    $parent.removeClass('open');
                }, settings.delay);
            });

            $this.hover(function() {
                if(settings.instantlyCloseOthers === true)
                    $allDropdowns.removeClass('open');

                window.clearTimeout(timeout);
                $parent.addClass('open');
            });

            $parent.find('.dropdown-submenu').each(function(){
                var $this = $(this);
                var subTimeout;
                $this.hover(function() {
                    window.clearTimeout(subTimeout);
                    $this.children('.dropdown-menu').show();

                    $this.siblings().children('.dropdown-menu').hide();
                }, function() {
                    var $submenu = $this.children('.dropdown-menu');
                    subTimeout = window.setTimeout(function() {
                        $submenu.hide();
                    }, settings.delay);
                });
            });
        });
    };

    $(document).ready(function() {
        $('[data-hover="dropdown"]').dropdownHover();
    });
})(jQuery, this);

调用示例:

<li class="dropdown">
    <a href="#" class="dropdown-toggle" data-toggle="dropdown" data-hover="dropdown" data-delay="1000" data-close-others="false">
        Account <b class="caret"></b>
    </a>
    <ul class="dropdown-menu">
        <li><a tabindex="-1" href="#">My Account</a></li>
        <li class="divider"></li>
        <li><a tabindex="-1" href="#">Change Email</a></li>
        <li><a tabindex="-1" href="#">Change Password</a></li>
        <li class="divider"></li>
        <li><a tabindex="-1" href="#">Logout</a></li>
    </ul>
</li>

阅读了该文章的人还浏览了...

本文永久链接码友网 » [Bootstrap]Bootstrap中如何使用jQuery实现下拉菜单(dropdown menu)在鼠标悬停时自动下拉展开菜单选项?

发布于: 2018-12-10 09:15:26
分享扩散:

发表评论

登录用户才能发表评论, 请 登 录 或者 注册