打开下拉菜单时 HTML 页面宽度发生变化

Question

我的导航栏有问题。当我打开下拉列表时，我的页面宽度在关闭时发生变化，我的页面恢复正常。

<link href="https://maxcdn.bootstrapcdn.com/font-awesome/4.7.0/css/font-awesome.min.css" rel="stylesheet" />
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0-beta.2/css/bootstrap.min.css" integrity="sha384-PsH8R72JQ3SOdhVi3uxftmaW6Vc51MKb0q5P2rRUpPvrszuE4W1povHYgTpBfshb" crossorigin="anonymous">
<script src="https://code.jquery.com/jquery-3.2.1.slim.min.js" integrity="sha384-KJ3o2DKtIkvYIK3UENzmM7KCkRr/rE9/Qpg6aAZGJwFDMVNA/GpGFF93hXpG5KkN" crossorigin="anonymous"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.12.3/umd/popper.min.js" integrity="sha384-vFJXuSJphROIrBnz7yo7oB41mKfc8JzQZiCq4NCceLEaO4IHwicKwpJf9c9IpFgh" crossorigin="anonymous"></script>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0-beta.2/js/bootstrap.min.js" integrity="sha384-alpBpkh1PFOepccYVYDB4do5UnbKysX5WZXm3XxPqe5iKTfUKjNkCk9SaVuEZflJ" crossorigin="anonymous"></script>
<nav class="navbar navbar-expand-lg navbar-light sticky-top">
    <div class="navbar-collapse" id="navbarTogglerDemo01">
        <ul id="forside" class="navbar-nav mr-auto">
            <a id="sidebarCollapse" class="navbar-brand" href="#"><i class="fa fa-list"></i></a>
        </ul>
        <ul class="navbar-nav pull-right">
            <li class="nav-item">
                <a class="nav-link" href="#"><span class="fa fa-envelope"></span></a>
            </li>
            <li class="nav-item dropdown">
                <a class="nav-link dropdown-toggle" href="#" id="navbarDropdown" role="button" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
                    Dropdown
                </a>
                <div class="dropdown-menu" aria-labelledby="navbarDropdown">
                    <a class="dropdown-item" href="#">Action</a>
                    <a class="dropdown-item" href="#">Another action</a>
                    <div class="dropdown-divider"></div>
                    <a class="dropdown-item" href="#">Something else here</a>
                </div>
            </li>
            <li class="nav-item">
                <a class="nav-link" href="#"><span class="fa fa-cogs"></span></a>
            </li>
        </ul>
    </div>
</nav>

这是我的下拉菜单关闭时的截图

这是我打开下拉菜单时的截图

如您所见，下面有一个卷轴。我需要先滚动它才能看到我的完整下拉元素。那么，我该如何解决呢？我不想滚动查看我的下拉项。对不起我的英语

Answer 1

给这个 css 以右对齐弹出窗口并删除滚动。 checkin 整页。

.navbar-expand-lg .navbar-nav .dropdown-menu {
    left: auto;    
    right: 0;
}

.navbar-expand-lg .navbar-nav .dropdown-menu {
    left: auto;    
    right: 0;
}

<link href="https://maxcdn.bootstrapcdn.com/font-awesome/4.7.0/css/font-awesome.min.css" rel="stylesheet" />
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0-beta.2/css/bootstrap.min.css" integrity="sha384-PsH8R72JQ3SOdhVi3uxftmaW6Vc51MKb0q5P2rRUpPvrszuE4W1povHYgTpBfshb" crossorigin="anonymous">
<script src="https://code.jquery.com/jquery-3.2.1.slim.min.js" integrity="sha384-KJ3o2DKtIkvYIK3UENzmM7KCkRr/rE9/Qpg6aAZGJwFDMVNA/GpGFF93hXpG5KkN" crossorigin="anonymous"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.12.3/umd/popper.min.js" integrity="sha384-vFJXuSJphROIrBnz7yo7oB41mKfc8JzQZiCq4NCceLEaO4IHwicKwpJf9c9IpFgh" crossorigin="anonymous"></script>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0-beta.2/js/bootstrap.min.js" integrity="sha384-alpBpkh1PFOepccYVYDB4do5UnbKysX5WZXm3XxPqe5iKTfUKjNkCk9SaVuEZflJ" crossorigin="anonymous"></script>
<nav class="navbar navbar-expand-lg navbar-light sticky-top">
  <div class="navbar-collapse" id="navbarTogglerDemo01">
    <ul id="forside" class="navbar-nav mr-auto">
      <a id="sidebarCollapse" class="navbar-brand" href="#"><i class="fa fa-list"></i></a>
    </ul>
    <ul class="navbar-nav pull-right">
      <li class="nav-item">
        <a class="nav-link" href="#"><span class="fa fa-envelope"></span></a>
      </li>
      <li class="nav-item dropdown">
        <a class="nav-link dropdown-toggle" href="#" id="navbarDropdown" role="button" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
        Dropdown
        </a>
        <div class="dropdown-menu" aria-labelledby="navbarDropdown">
          <a class="dropdown-item" href="#">Action</a>
          <a class="dropdown-item" href="#">Another action</a>
          <div class="dropdown-divider"></div>
          <a class="dropdown-item" href="#">Something else here</a>
        </div>
      </li>
      <li class="nav-item">
        <a class="nav-link" href="#"><span class="fa fa-cogs"></span></a>
      </li>
    </ul>
  </div>
</nav>