这是一款基于bootsnav的js和CSS3多级导航菜单效果。该多级导航菜单效果在bootsnav菜单的基础上进行了美化，使效果更加炫酷。

使用方法

在页面中引入bootstrap相关文件,jquery和bootsnav文件。

HTML结构

该js和CSS3多级导航菜单的HTML结构如下：

CSS样式

然后通过下面的CSS代码来对该js和CSS3多级导航菜单进行美化。

nav.navbar.bootsnav{
    border: none;
    background: none;
    margin-bottom: 150px;
}
nav.navbar.bootsnav ul.nav > li{
    margin-right: 10px;
}
nav.navbar.bootsnav ul.nav > li:before{
    content: "";
    width: 2px;
    height: 0;
    background: #fff;
    margin: 0 auto;
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    transition: all 0.5s ease 0s;
}
nav.navbar.bootsnav ul.nav > li:hover:before{ height: 25px; }
nav.navbar.bootsnav ul.nav > li.megamenu-fw:before{ left: 11.3%; }
nav.navbar.bootsnav ul.nav > li:after{
    content: "";
    width: 10px;
    height: 10px;
    border-radius: 50%;
    background: #fff;
    margin: 0 auto;
    position: absolute;
    bottom: 70px;
    left: 0;
    right: 0;
    opacity: 0;
    transition: all 0.5s ease 0s;
}
nav.navbar.bootsnav ul.nav > li:hover:after{
    bottom: 20px;
    opacity: 1;
}
nav.navbar.bootsnav ul.nav > li.megamenu-fw:after{ left: 11.3%; }
nav.navbar.bootsnav ul.nav > li > a{
    padding: 15px 15px 35px 15px;
    margin: 0;
    color: #fff;
    text-transform: uppercase;
    z-index: 1;
    transition: all 0.5s ease 0s;
}
nav.navbar.bootsnav ul.nav > li.dropdown > a{
    padding: 15px 30px 35px 15px;
}
nav.navbar.bootsnav ul.nav > li > a:hover{ color: #fff; }
nav.navbar.bootsnav ul.nav > li.dropdown > a.dropdown-toggle:after{
    position: absolute;
    margin: 0 0 0 7px;
}
nav.navbar.bootsnav ul.nav > li.dropdown > ul{
    top: 120%;
    transition: all 0.8s ease 0s;
}
nav.navbar.bootsnav ul.nav > li.dropdown.on > ul{
    top: 100%;
}
.dropdown-menu.multi-dropdown{
    position: absolute;
    left: -100% !important;
}
nav.navbar.bootsnav li.dropdown ul.dropdown-menu{
    box-shadow: 0 0 10px rgba(0, 0, 0, 0.3);
    border: none;
}
nav.navbar.bootsnav li.dropdown ul.dropdown-menu.megamenu-content li{
    font-size: 14px;
    color: #6f6f6f;
}
nav.navbar.bootsnav li.dropdown ul.dropdown-menu.megamenu-content .title{
    font-size: 16px;
    font-weight: bold;
    color: #3f3f3f;
}
@media only screen and (max-width:990px){
    .dropdown-menu.multi-dropdown{ left: 0 !important; }
    nav.navbar.bootsnav .navbar-toggle{
        background: none;
        color: #fff;
    }
    nav.navbar.bootsnav ul.nav > li{
        margin-right: 0;
    }
    nav.navbar.bootsnav ul.nav > li:before{
        width: 0;
        height: 2px;
        background: #dca342;
        margin: 0;
        bottom: 50%;
        left: 0;
    }
    nav.navbar.bootsnav ul.nav > li:hover:before{
        width: 25px;
        height: 2px;
    }
    nav.navbar.bootsnav ul.nav > li.megamenu-fw:before{
        left: 0;
        bottom: 52%;
    }
    nav.navbar.bootsnav ul.nav > li:after,
    nav.navbar.bootsnav ul.nav > li.megamenu-fw:after{
        background: #dca342;
        margin: 0;
        bottom: 50%;
        left: auto;
        right: 0;
    }
    nav.navbar.bootsnav ul.nav > li:hover:after{
        bottom: 42%;
        right: 90%;
    }
    nav.navbar.bootsnav ul.nav > li:hover.megamenu-fw:after{
        bottom: 51.3%;
    }
    nav.navbar.bootsnav.navbar-mobile ul.nav > li > a{
        padding: 15px;
        text-align: center;
    }
    nav.navbar.bootsnav ul.nav > li > a,
    nav.navbar.bootsnav ul.nav > li > a:hover{
        color: #333;
    }
    nav.navbar.bootsnav ul.nav > li.dropdown > ul{ top: 100%; }
    nav.navbar.bootsnav ul.nav > li.dropdown.on:before,
    nav.navbar.bootsnav ul.nav > li.dropdown.on:after{
        display: none;
    }
    nav.navbar.bootsnav li.dropdown ul.dropdown-menu.megamenu-content .title{
        font-size: 14px;
        font-weight: normal;
    }
}