jQuery代码以检查div没有类不起作用 [英] JQuery code to check that div does not have class not working

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问题描述

我有一些JQuery代码，可以使Bootstrap导航栏下拉菜单在鼠标悬停时自动展开.我有一个下拉菜单用作语言菜单，其中只有一个标志图标.对于这个div，我分配了一个自定义CSS类，该类在下拉菜单中隐藏了carot.

I have some JQuery code that enables Bootstrap navbar dropdown menus to automatically expand on mouseover. I have one dropdown menu that I am using as a language menu, which just has a flag icon. For this div I assign a custom CSS class which hides the carot in the dropdown menu.

我正在尝试让JQuery检查div是否被分配了一个"carot-off"类，如果是这种情况，则将其忽略，但是我所拥有的不起作用.

I am trying to get JQuery to check if the div is assigned a class 'carot-off' and ignore it if that is the case, but what I have is not working.

到目前为止，这是我的代码:

This is my code so far:

.caret-off::before {
    display: none;
}
.caret-off::after {
    display: none;
}

<html>
    <head>
    <script src="https://code.jquery.com/jquery-3.5.1.slim.min.js" integrity="sha384-DfXdz2htPH0lsSSs5nCTpuj/zy4C+OGpamoFVy38MVBnE+IbbVYUew+OrCXaRkfj" crossorigin="anonymous"></script>
    <script src="https://cdn.jsdelivr.net/npm/popper.js@1.16.0/dist/umd/popper.min.js" integrity="sha384-Q6E9RHvbIyZFJoft+2mJbHaEWldlvI9IOYy5n3zV9zzTtmI3UksdQRVvoxMfooAo" crossorigin="anonymous"></script>
    <link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.5.0/css/bootstrap.min.css" integrity="sha384-9aIt2nRpC12Uk9gS9baDl411NQApFmC26EwAOH8WgZl5MYYxFfc+NcPb1dKGj7Sk" crossorigin="anonymous">
    <script src="https://stackpath.bootstrapcdn.com/bootstrap/4.5.0/js/bootstrap.min.js" integrity="sha384-OgVRvuATP1z7JjHLkuOU7Xw704+h835Lr+6QL9UvYjZE3Ipu6Tp75j7Bh/kR0JKI" crossorigin="anonymous"></script>
    </head>
    <body>
    <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="#navbarNavDropdown" aria-controls="navbarNavDropdown" aria-expanded="false" aria-label="Toggle navigation">
    <span class="navbar-toggler-icon"></span>
  </button>
      <div class="collapse navbar-collapse" id="navbarNavDropdown">
        <ul class="navbar-nav">
          <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="#">Features</a>
          </li>
          <li class="nav-item">
            <a class="nav-link" href="#">Pricing</a>
          </li>
          <li class="nav-item dropdown">
            <a class="nav-link dropdown-toggle" href="#" id="navbarDropdownMenuLink" role="button" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
              Dropdown link
            </a>
            <div class="dropdown-menu" aria-labelledby="navbarDropdownMenuLink">
              <a class="dropdown-item" href="#">Action</a>
              <a class="dropdown-item" href="#">Another action</a>
              <a class="dropdown-item" href="#">Something else here</a>
            </div>
          </li>
          <li class="nav-item dropdown">
            <a class="nav-link dropdown-toggle caret-off" href="#" id="navbarDropdownMenuLink" role="button" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
              Dropdown link
            </a>
            <div class="dropdown-menu" aria-labelledby="navbarDropdownMenuLink">
              <a class="dropdown-item" href="#">Action</a>
              <a class="dropdown-item" href="#">Another action</a>
              <a class="dropdown-item" href="#">Something else here</a>
            </div>
          </li>
        </ul>
      </div>
    </nav>
<script>
const $dropdown = $(".dropdown");
const $dropdownToggle = $(".dropdown-toggle");
const $dropdownMenu = $(".dropdown-menu");
const showClass = "show";
 
$(window).on("load resize", function() {
  if (this.matchMedia("(min-width: 768px)").matches) {
    $dropdown.hover(
      function() {
        const $this = $(this);
        $this.addClass(showClass);
        if (!$(this).hasClass("caret-off")) {
        $this.find($dropdownToggle).attr("aria-expanded", "true");
        $this.find($dropdownMenu).addClass(showClass);
        }
      },
      function() {
        const $this = $(this);
        $this.removeClass(showClass);
        if (!$(this).hasClass("caret-off")) {
        $this.find($dropdownToggle).attr("aria-expanded", "false");
        $this.find($dropdownMenu).removeClass(showClass);
        }
      }
    );
  } else {
    $dropdown.off("mouseenter mouseleave");
  }
});
</script>
    </body>
    </html>

使用if (!$(this).hasClass("caret-off"))似乎应该是正确的，但是完全没有效果.难道我做错了什么?我的方法不正确吗?

Using if (!$(this).hasClass("caret-off")) seems like it should be correct, but it has no effect at all. Am I doing something wrong? Is my approach incorrect?

推荐答案

caret-off类被赋予具有dropdown-toggle类的HTML锚标记. 代码正在检查条件$(this).hasClass("caret-off")，此条件已应用于HTML元素$(".dropdown").

caret-off class is given to HTML anchor tags having class as dropdown-toggle.
And the code was checking the condition $(this).hasClass("caret-off"), this condition was getting applied to HTML elements $(".dropdown").

因此将条件更正为$(this).find($dropdownToggle).hasClass("caret-off")，该条件检查是否要切换的下拉元素具有caret-off类.如果该元素没有caret-off类，则仅子菜单将被扩展.

So corrected the condition to $(this).find($dropdownToggle).hasClass("caret-off"), which checks whether gonna be toggle dropdown element have caret-off class or not. If that element don't have a caret-off class then only submenus will get expanded.

为了展示有效的答案，我评论了检查响应性的条件.您可以添加它.

To demonstrate the working answer, I have commented the condition to check responsiveness. Which you can add it.

const $dropdown = $(".dropdown");
const $dropdownToggle = $(".dropdown-toggle");
const $dropdownMenu = $(".dropdown-menu");
const showClass = "show";
 
$(window).on("load resize", function() {
  //if (this.matchMedia("(min-width: 768px)").matches) {
    $dropdown.hover(
      function() {
        const $this = $(this);
        $this.addClass(showClass);
        if (!$(this).find($dropdownToggle).hasClass("caret-off")) {
        $this.find($dropdownToggle).attr("aria-expanded", "true");
        $this.find($dropdownMenu).addClass(showClass);
        }
      },
      function() {
        const $this = $(this);
        $this.removeClass(showClass);
        if (!$(this).find($dropdownToggle).hasClass("caret-off")) {
        $this.find($dropdownToggle).attr("aria-expanded", "false");
        $this.find($dropdownMenu).removeClass(showClass);
        }
      }
    );
  //} else {
  //  $dropdown.off("mouseenter mouseleave");
  //}
});

.caret-off::before {
    display: none!important;
}
.caret-off::after {
    display: none!important;
}

<html>
<head>
<script src="https://code.jquery.com/jquery-3.5.1.slim.min.js" integrity="sha384-DfXdz2htPH0lsSSs5nCTpuj/zy4C+OGpamoFVy38MVBnE+IbbVYUew+OrCXaRkfj" crossorigin="anonymous"></script>
<script src="https://cdn.jsdelivr.net/npm/popper.js@1.16.0/dist/umd/popper.min.js" integrity="sha384-Q6E9RHvbIyZFJoft+2mJbHaEWldlvI9IOYy5n3zV9zzTtmI3UksdQRVvoxMfooAo" crossorigin="anonymous"></script>
<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.5.0/css/bootstrap.min.css" integrity="sha384-9aIt2nRpC12Uk9gS9baDl411NQApFmC26EwAOH8WgZl5MYYxFfc+NcPb1dKGj7Sk" crossorigin="anonymous">
<script src="https://stackpath.bootstrapcdn.com/bootstrap/4.5.0/js/bootstrap.min.js" integrity="sha384-OgVRvuATP1z7JjHLkuOU7Xw704+h835Lr+6QL9UvYjZE3Ipu6Tp75j7Bh/kR0JKI" crossorigin="anonymous"></script>
</head>
<body>
<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="#navbarNavDropdown" aria-controls="navbarNavDropdown" aria-expanded="false" aria-label="Toggle navigation">
<span class="navbar-toggler-icon"></span>
</button>
  <div class="collapse navbar-collapse" id="navbarNavDropdown">
    <ul class="navbar-nav">
      <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="#">Features</a>
      </li>
      <li class="nav-item">
        <a class="nav-link" href="#">Pricing</a>
      </li>
      <li class="nav-item dropdown">
        <a class="nav-link dropdown-toggle" href="#" id="navbarDropdownMenuLink" role="button" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
          Dropdown link
        </a>
        <div class="dropdown-menu" aria-labelledby="navbarDropdownMenuLink">
          <a class="dropdown-item" href="#">Action</a>
          <a class="dropdown-item" href="#">Another action</a>
          <a class="dropdown-item" href="#">Something else here</a>
        </div>
      </li>
      <li class="nav-item dropdown">
        <a class="nav-link dropdown-toggle caret-off" href="#" id="navbarDropdownMenuLink" role="button" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
          Dropdown link
        </a>
        <div class="dropdown-menu" aria-labelledby="navbarDropdownMenuLink">
          <a class="dropdown-item" href="#">Action</a>
          <a class="dropdown-item" href="#">Another action</a>
          <a class="dropdown-item" href="#">Something else here</a>
        </div>
      </li>
    </ul>
  </div>
</nav>
</body>
</html>

这篇关于jQuery代码以检查div没有类不起作用的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！

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