具有滾動條的多級下拉菜單

Question

我有滾動條的多級下拉菜單。 但它不會顯示3level子菜單。 請在這方面建議我。

 .dropdown-submenu { position: relative; } .dropdown-submenu>.dropdown-menu { top: 0; left: 100%; margin-top: -6px; margin-left: -1px; -webkit-border-radius: 0 6px 6px 6px; -moz-border-radius: 0 6px 6px; border-radius: 0 6px 6px 6px; overflow-y: scroll; overflow-x: hidden; height: 80px; } .dropdown-submenu:hover>.dropdown-menu { display: block; } .dropdown-submenu>a:after { display: block; content: " "; float: right; width: 0; height: 0; border-color: transparent; border-style: solid; border-width: 5px 0 5px 5px; border-left-color: #ccc; margin-top: 5px; margin-right: -10px; } .dropdown-submenu:hover>a:after { border-left-color: #fff; } .dropdown-submenu.pull-left { float: none; } .dropdown-submenu.pull-left>.dropdown-menu { left: -100%; margin-left: 10px; -webkit-border-radius: 6px 0 6px 6px; -moz-border-radius: 6px 0 6px 6px; border-radius: 6px 0 6px 6px; } 

 <link href="http://netdna.bootstrapcdn.com/bootstrap/3.1.1/css/bootstrap.min.css" rel="stylesheet"/> <script src="http://netdna.bootstrapcdn.com/bootstrap/3.1.1/js/bootstrap.min.js"></script> <div class="container"> <div class="row"> <div class="dropdown"> <a id="dLabel" role="button" data-toggle="dropdown" class="btn btn-primary" data-target="#" href="/page.html"> Dropdown <span class="caret"></span> </a> <ul class="dropdown-menu multi-level" role="menu" aria-labelledby="dropdownMenu"> <li><a href="#">Some action</a></li> <li><a href="#">Some other action</a></li> <li class="divider"></li> <li class="dropdown-submenu"> <a tabindex="-1" href="#">Hover me for more options</a> <ul class="dropdown-menu"> <li><a tabindex="-1" href="#">Second level</a></li> <li class="dropdown-submenu"> <a href="#">Even More..</a> <ul class="dropdown-menu"> <li><a href="#">3rd level</a></li> <li><a href="#">3rd level</a></li> <li><a href="#">3rd level</a></li> <li><a href="#">3rd level</a></li> <li><a href="#">3rd level</a></li> <li><a href="#">3rd level</a></li> <li><a href="#">3rd level</a></li> </ul> </li> <li><a href="#">Second level</a></li> <li><a href="#">Second level</a></li> </ul> </li> </ul> </div> </div> </div> 

我希望子菜單應該從頂部開始。 像這樣的東西https://ibb.co/jWeFwk ， https://ibb.co/goO8Gk好心通過它與建議我需要在CSS的變化。

Answer 1

.dropdown-submenu>.dropdown-menu {
    top: 0;
    left: 100%;
    margin-top: -6px;
    margin-left: -1px;
    -webkit-border-radius: 0 6px 6px 6px;
    -moz-border-radius: 0 6px 6px;
    border-radius: 0 6px 6px 6px;

    /**
      * It's unnecessary.
      */
    /* overflow-y: scroll;
    overflow-x: scroll; 
    height: 80px; */
}

Answer 2

在這里查看更新的小提琴： 小提琴

<div class="container">
<div class="row">

    <div class="dropdown">
        <a id="dLabel" role="button" data-toggle="dropdown" class="btn btn-primary" data-target="#" href="/page.html">
            Dropdown <span class="caret"></span>
        </a>
        <ul class="dropdown-menu multi-level" role="menu" aria-labelledby="dropdownMenu">
          <li><a href="#">Some action</a></li>
          <li><a href="#">Some other action</a></li>
          <li class="divider"></li>
          <li class="dropdown-submenu">
            <a tabindex="-1" href="#">Hover me for more options</a>
            <ul class="dropdown-menu">
              <li><a tabindex="-1" href="#">Second level</a></li>
              <li class="dropdown-submenu">
                <a href="#">Even More..</a>
                <ul class="dropdown-menu dropdown-menu-3">
                    <li><a href="#">3rd level</a></li>
                    <li><a href="#">3rd level</a></li>
                    <li><a href="#">3rd level</a></li>
                    <li><a href="#">3rd level</a></li>
                    <li><a href="#">3rd level</a></li>
                    <li><a href="#">3rd level</a></li>
                    <li><a href="#">3rd level</a></li>
                </ul>
              </li>
              <li><a href="#">Second level</a></li>
              <li><a href="#">Second level</a></li>
            </ul>
          </li>
        </ul>
    </div>
</div>

CSS：

.dropdown-submenu {
    position: relative;
}

.dropdown-submenu>.dropdown-menu {
    top: 0;
    left: 100%;
    margin-top: -6px;
    margin-left: -1px;
    -webkit-border-radius: 0 6px 6px 6px;
    -moz-border-radius: 0 6px 6px;
    border-radius: 0 6px 6px 6px;
    height: 120px;
}
.dropdown-submenu>.dropdown-menu-3{
    height: 196px;
}
.dropdown-submenu:hover>.dropdown-menu {
    display: block;
}

.dropdown-submenu>a:after {
    display: block;
    content: " ";
    float: right;
    width: 0;
    height: 0;
    border-color: transparent;
    border-style: solid;
    border-width: 5px 0 5px 5px;
    border-left-color: #ccc;
    margin-top: 5px;
    margin-right: -10px;
}

.dropdown-submenu:hover>a:after {
    border-left-color: #fff;
}

.dropdown-submenu.pull-left {
    float: none;
}

.dropdown-submenu.pull-left>.dropdown-menu {
    left: -100%;
    margin-left: 10px;
    -webkit-border-radius: 6px 0 6px 6px;
    -moz-border-radius: 6px 0 6px 6px;
    border-radius: 6px 0 6px 6px;
}