更改菜单标题仅在第一次后发生

Question

我有一个 bootstrap 菜单。如果它是折叠的，我希望它有页面的名称，如果它是打开的，我希望它命名菜单。

现在我将其命名为 "Watch the Trailer"（假设在该页面上的位置）。单击按钮时，更改标题有效，但仅在第一次后有效。这是为什么？

var menu_title = $(".so_menu_name").html();
    
$(".navbar button").on("click", function () {
  var collapsed = $(".navbar button").hasClass("collapsed");
  if (!collapsed) {
    $(".so_menu_name").html(menu_title);
  }
  else {
    $(".so_menu_name").html("Menu");
  }
});

.nav.navbar-nav .nav-item {
      float: none;
}

.nav.navbar-nav .nav-item+.nav-item {
      margin-left: 0;
}
.nav.navbar-nav .nav-link {
      padding: .25rem 0;
}
.nav.os_menu {
      border-top: 2px solid rgba(255, 255, 255, .5);
      border-bottom: 2px solid rgba(255, 255, 255, .5);
}

<div class="container">

  <nav class="navbar navbar-dark bg-inverse">
    <span class="so_menu_name">Watch the Trailer</span>
    <button class="navbar-toggler hidden-sm-up" type="button" data-toggle="collapse" data-target="#collapsingNavbar">+</button>

    <div class="collapse navbar-toggleable-xs" id="collapsingNavbar">

      <ul class="nav navbar-nav os_menu">
        <li class="nav-item active">
          <a class="nav-link" href="#">Watch the Trailer<span class="sr-only">(current)</span></a>
        </li>
        <li class="nav-item">
          <a class="nav-link" href="#">Screening & Events</a>
        </li>
        <li class="nav-item">
          <a class="nav-link" href="#">Synopsis</a>
        </li>
        <li class="nav-item">
          <a class="nav-link" href="#">The Protagonist</a>
        </li>
      </ul>

    </div>
  </nav>

</div>


<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>

Answer 1

试试这个：DEMO

我在按钮内添加文字。

<button class="navbar-toggler hidden-sm-up" type="button" data-toggle="collapse" data-target="#collapsingNavbar">
   Watch the Trailer +
  </button>

Answer 2

我的建议是：

这些行的主要变化：

<div class="navbar-toggleable-xs collapse in" id="collapsingNavbar">

和：

<button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#collapsingNavbar">
    <span class="so_menu_name">Watch the Trailer</span>
</button>

$(function () {
  var menu_title = $(".so_menu_name").html();

  $("button.navbar-toggler").on("click", function (e) {
    e.preventDefault();
    var collapsed = $(this).hasClass("collapsed");
    if (collapsed) {
      $(".so_menu_name").text(menu_title);
    }
    else {
      $(".so_menu_name").text("Menu");
    }
  });
});

.nav.navbar-nav .nav-item {
  float: none;
}
.nav.navbar-nav .nav-item+.nav-item {
  margin-left: 0;
}
.nav.navbar-nav .nav-link {
  padding: .25rem 0;
}
.nav.os_menu {
  border-top: 2px solid rgba(255,255,255,.5);
  border-bottom: 2px solid rgba(255,255,255,.5);
}

<link href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0-alpha.2/css/bootstrap.min.css" rel="stylesheet">
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.4/jquery.min.js"></script>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0-alpha.2/js/bootstrap.min.js"></script>


<div class="container">
    <nav class="navbar navbar-dark bg-inverse">
        <button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#collapsingNavbar">
            <span class="so_menu_name">Watch the Trailer</span>
        </button>
        <div class="navbar-toggleable-xs collapse in" id="collapsingNavbar">
            <ul class="nav navbar-nav os_menu">
                <li class="nav-item active">
                    <a class="nav-link" href="#">Watch the Trailer<span class="sr-only">(current)</span></a>
                </li>
                <li class="nav-item">
                    <a class="nav-link" href="#">Screening & Events</a>
                </li>
                <li class="nav-item">
                    <a class="nav-link" href="#">Synopsis</a>
                </li>
                <li class="nav-item">
                    <a class="nav-link" href="#">The Protagonist</a>
                </li>
            </ul>
        </div>
    </nav>
</div>

Answer 3

我分析的可能是插件有问题。对于第一次点击，它不会添加或删除名为 collapse.

的 class

如果你使用它的属性aria-expanded你可能会解决这个问题。

var menu_title = $(".so_menu_name").html();

$(".navbar button").on("click", function () {
//  var collapsed = $(".navbar button").hasClass("collapsed");
if ($(this).attr('aria-expanded') == "true") {
  $(".so_menu_name").html(menu_title);
}
else {
  $(".so_menu_name").html("Menu");
}

});

Try fiddle.

更改菜单标题仅在第一次后发生

Changing menu title only happens after first time

jquery

css

twitter-bootstrap

twitter-bootstrap-4