Javascript 引导上的下拉子菜单不工作

我只是想问一下为什么bootstrap上的下拉子菜单不起作用，我只是按照这个链接中的说明：（）但子菜单上的下拉子菜单仍然没有出现。顺便说一下，我没有在CSS中更改或重写类

这是我的密码！：）

请验证您所遵循的说明是否与引导版本一致

此外，您可以尝试包括这几行CSS，以使事情顺利进行

.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;
}

.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;
}

---

我做了，但问题是“取款/存款”和“定期存款”的子菜单阻止了父子菜单“交易”，悬停时它不会转到它的右侧。这是我的代码

        <li class='dropdown'><a id = 'dLabel' class='dropdown-toggle active' data-toggle='dropdown' href='#'><img src = 'images/forbank.png' height = 35 width = 35>Banking<span class='caret'></span></a>
            <ul class='dropdown-menu multi-level' role='menu' aria-labelledby='dropdownMenu'>
                <li class = 'dropdown-submenu'>
                <a  tabindex = '-1' href='#'><span class = 'glyphicon glyphicon-cog'> </span>  Transaction </a>
                    <ul class='dropdown-menu'>
                        <li><a tabindex='-1' href='#'> Withdrawal / Deposit </a></li>
                        <li><a tabindex='-1' href='#'> Fixed Deposit </a></li>
                    </ul>
                </li>
                <li role='separator' class='divider'></li>
                <li><a href='#'><span class='glyphicon glyphicon-list-alt'> </span> Summaries </a></li>
                <li><a href='#'><span class='glyphicon glyphicon-wrench'> </span>  Settings </a></li>
            </ul>
        </li>

我建议使用最新版本的引导。版本2.3.2已过期，版本3.3.5是最新版本。我刚刚读到，类下拉菜单已被删除到最新版本的CCS中，最新版本的T没有替代类。T我该怎么办？创建新的CSS文件，粘贴上面的代码，并将CSS链接到html

        <li class='dropdown'><a id = 'dLabel' class='dropdown-toggle active' data-toggle='dropdown' href='#'><img src = 'images/forbank.png' height = 35 width = 35>Banking<span class='caret'></span></a>
            <ul class='dropdown-menu multi-level' role='menu' aria-labelledby='dropdownMenu'>
                <li class = 'dropdown-submenu'>
                <a  tabindex = '-1' href='#'><span class = 'glyphicon glyphicon-cog'> </span>  Transaction </a>
                    <ul class='dropdown-menu'>
                        <li><a tabindex='-1' href='#'> Withdrawal / Deposit </a></li>
                        <li><a tabindex='-1' href='#'> Fixed Deposit </a></li>
                    </ul>
                </li>
                <li role='separator' class='divider'></li>
                <li><a href='#'><span class='glyphicon glyphicon-list-alt'> </span> Summaries </a></li>
                <li><a href='#'><span class='glyphicon glyphicon-wrench'> </span>  Settings </a></li>
            </ul>
        </li>