Bootstrap: navbar: open on hover?

Question

I have a bootstrap 4 navbar menu:

<nav class="navbar navbar-expand-lg navbar-light bg-light">
  <a class="navbar-brand" href="#">Navbar</a>
  <button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarSupportedContent" aria-controls="navbarSupportedContent" aria-expanded="false" aria-label="Toggle navigation">
    <span class="navbar-toggler-icon"></span>
  </button>

  <div class="collapse navbar-collapse" id="navbarSupportedContent">
    <ul class="navbar-nav mr-auto">
      <li class="nav-item active">
        <a class="nav-link" href="#">Home <span class="sr-only">(current)</span></a>
      </li>
      <li class="nav-item">
        <a class="nav-link" href="#">Link</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 disabled" href="#">Disabled</a>
      </li>
    </ul>
    <form class="form-inline my-2 my-lg-0">
      <input class="form-control mr-sm-2" type="search" placeholder="Search" aria-label="Search">
      <button class="btn btn-outline-success my-2 my-sm-0" type="submit">Search</button>
    </form>
  </div>
</nav>

So normally, dropdown menu opens on click. It's okay for mobile devices but I want it open on hover for big screens. So when navbar menu is collapsed it should open on click but if it's not it should open on hover. How can I achieve that?

Answer 1

Use a @media query for the breakpoint of the navbar-expand-lg:

@media (min-width: 992px) {
    .dropdown:hover .dropdown-menu {
        display: block;
    }
}

https://www.codeply.com/go/uFPbKuv8GO

Answer 2

The fundamental part of the answers given here is:

@media (min-width: 992px) {
    .dropdown:hover .dropdown-menu {
        display: block;
    }
}

This works, but has a defect. Say you hover the mouse over .dropdown. The .dropdown-menu appears. When you lower the mouse into .dropdown-menu, it will close if you don't move the mouse fast enough, as the "hover" condition is lost at the border between .dropdown and .dropdown-menu.

This can be fixed by nudging the position of .dropdown-menu upwards, so there is no border where the "hover" condition is lost.

The default bootstrap position of .dropdown-menu is top: 100%. Override that as follows:

@media (min-width: 992px) {
    .dropdown:hover .dropdown-menu {
        display: block;
        top: 95%; 
    }
}

This way the dropdown stays open even if the user moves the mouse into it slowly.