javascript - 修复导航栏子菜单离开屏幕的问题

Question

我正在使用以下脚本作为导航栏，但是我不知道如何使菜单/子菜单尊重屏幕两侧，而不是继续在屏幕边框之外打开。我不想更改默认行为所有菜单的（方向），只是为了改变它，它会被任何一侧切割..

我找到了一个类似的帖子（还有另一个帖子），但我不知道如何对当前代码实现相同的答案。

屏幕旁边的菜单示例：

这是代码片段，以及jsfiddle链接。

$(document).ready(function() {

  /* MAIN MENU */
  $('#main-menu > li:has(ul.sub-menu)').addClass('parent');
  $('ul.sub-menu > li:has(ul.sub-menu) > a').addClass('parent');

  $('#menu-toggle').click(function() {
    $('#main-menu').slideToggle(300);
    return false;
  });

  $(window).resize(function() {
    if ($(window).width() > 700) {
      $('#main-menu').removeAttr('style');
    }
  });

});

body {
  background-color: #eee;
  background-image: url(../images/patterns/light_toast.png);
  color: #666;
  font-family: 'Open Sans', sans-serif;
  font-size: 12px;
  margin: 0px;
  padding: 0px;
}

a {
  color: #23dbdb;
  text-decoration: none;
}

a:hover {
  color: #000;
}

ol,
ul {
  list-style: none;
  padding: 0px;
  margin: 0px;
}

#wrap {
  margin: 0 auto;
}

.inner {
  margin: 0 auto;
  max-width: 940px;
  padding: 0 40px;
}

.relative {
  position: relative;
}

.right {
  float: right;
}

.left {
  float: left;
}


/* HEADER */

#wrap>header {
  background-color: #333;
  padding-bottom: 20px;
}

.logo {
  display: inline-block;
  font-size: 0;
  padding-top: 15px;
}

#navigation {
  position: absolute;
  right: 40px;
  bottom: 0px;
}

#menu-toggle {
  display: none;
  float: right;
}


/* HEADER > MENU */

#main-menu {
  float: right;
  font-size: 0;
  margin: 10px 0;
}

#main-menu>li {
  display: inline-block;
  margin-left: 30px;
  padding: 2px 0;
}

#main-menu>li.parent {
  background-image: url(../images/plus-gray.png);
  background-size: 7px 7px;
  background-repeat: no-repeat;
  background-position: left center;
}

#main-menu>li.parent>a {
  padding-left: 14px;
}

#main-menu>li>a {
  color: #eee;
  font-size: 14px;
  line-height: 14px;
  padding: 30px 0;
  text-decoration: none;
}

#main-menu>li:hover>a,
#main-menu>li.current-menu-item>a {
  color: #23dbdb;
}


/* HEADER > MENU > DROPDOWN */

#main-menu li {
  position: relative;
}

ul.sub-menu {
  /* level 2 */
  display: none;
  left: 0px;
  top: 38px;
  padding-top: 10px;
  position: absolute;
  width: 150px;
  z-index: 9999;
}

ul.sub-menu ul.sub-menu {
  /* level 3+ */
  margin-top: -1px;
  padding-top: 0;
  left: 149px;
  top: 0px;
}

ul.sub-menu>li>a {
  background-color: #333;
  border: 1px solid #444;
  border-top: none;
  color: #bbb;
  display: block;
  font-size: 12px;
  line-height: 15px;
  padding: 10px 12px;
}

ul.sub-menu>li>a:hover {
  background-color: #2a2a2a;
  color: #fff;
}

ul.sub-menu>li:first-child {
  border-top: 3px solid #23dbdb;
}

ul.sub-menu ul.sub-menu>li:first-child {
  border-top: 1px solid #444;
}

ul.sub-menu>li:last-child>a {
  border-radius: 0 0 2px 2px;
}

ul.sub-menu>li>a.parent {
  background-image: url(../images/arrow.png);
  background-size: 5px 9px;
  background-repeat: no-repeat;
  background-position: 95% center;
}

#main-menu li:hover>ul.sub-menu {
  display: block;
  /* show the submenu */
}

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/2.2.3/jquery.min.js"></script>
<div id="wrap">
  <header>
    <div class="inner relative">
      <a class="logo" href="#"><img src="https://www.gravatar.com/avatar/851659509f07dd2fe27882da61f0da0a?s=64" alt="fresh design web"></a>
      <a id="menu-toggle" class="button dark" href="#"><i class="icon-reorder"></i></a>
      <nav id="navigation">
        <ul id="main-menu">
          <li class="current-menu-item"><a href="http://www.freshdesignweb.com">Home</a></li>
          <li class="parent">
            <a href="#">Features</a>
            <ul class="sub-menu">
              <li><a href="#"><i class="icon-wrench"></i> Elements</a></li>
              <li><a href="#"><i class="icon-credit-card"></i>  Pricing Tables</a></li>
              <li><a href="#"><i class="icon-gift"></i> Icons</a></li>
              <li>
                <a class="parent" href="#"><i class="icon-file-alt"></i> Pages</a>
                <ul class="sub-menu">
                  <li><a href="#">Full Width</a></li>
                  <li><a href="#">Left Sidebar</a></li>
                  <li><a href="#">Right Sidebar</a></li>
                  <li><a href="#">Double Sidebar</a></li>
                </ul>
              </li>
            </ul>
          </li>
          <li><a href="#">Portfolio</a></li>
          <li class="parent">
            <a href="#">Blog</a>
            <ul class="sub-menu">
              <li><a href="#">Large Image</a></li>
              <li><a href="#">Medium Image</a></li>
              <li><a href="#">Masonry</a></li>
              <li>
                <a class="parent" href="#"><i class="icon-file-alt"></i> Pages ></a>
                <ul class="sub-menu">
                  <li><a href="#">Full Width</a></li>
                  <li><a href="#">Left Sidebar</a></li>
                  <li><a href="#">Right Sidebar</a></li>
                  <li><a href="#">Double Sidebar</a></li>
                </ul>
              </li>
              <li><a href="#">Double Sidebar</a></li>
              <li><a href="#">Single Post</a></li>
            </ul>
          </li>
          <li><a href="#">Contact</a></li>
        </ul>
      </nav>
      <div class="clear"></div>
    </div>
  </header>

标签： javascriptjqueryhtmlcssdrop-down-menu

Answer 1

在您的子子菜单中，您基于 149 像素的左边距对齐，只需使用相同的属性而不是右边距。right:149px;代替left:149px;

ul.sub-menu ul.sub-menu {
  /* level 3+ */
  right: 149px;
}

您也可以将子菜单对齐到导航项目的左侧。为此，请使用：

ul.sub-menu { 
  /* level 2 */
  right: 0;
  left: initial;
}

我在这个片段中包含了这两个例子：

$(document).ready(function() {

  /* MAIN MENU */
  $('#main-menu > li:has(ul.sub-menu)').addClass('parent');
  $('ul.sub-menu > li:has(ul.sub-menu) > a').addClass('parent');

  $('#menu-toggle').click(function() {
    $('#main-menu').slideToggle(300);
    return false;
  });

  $(window).resize(function() {
    if ($(window).width() > 700) {
      $('#main-menu').removeAttr('style');
    }
  });

});

body {
  background-color: #eee;
  background-image: url(../images/patterns/light_toast.png);
  color: #666;
  font-family: 'Open Sans', sans-serif;
  font-size: 12px;
  margin: 0px;
  padding: 0px;
}

a {
  color: #23dbdb;
  text-decoration: none;
}

a:hover {
  color: #000;
}

ol,
ul {
  list-style: none;
  padding: 0px;
  margin: 0px;
}

#wrap {
  margin: 0 auto;
}

.inner {
  margin: 0 auto;
  max-width: 940px;
  padding: 0 40px;
}

.relative {
  position: relative;
}

.right {
  float: right;
}

.left {
  float: left;
}


/* HEADER */

#wrap>header {
  background-color: #333;
  padding-bottom: 20px;
}

.logo {
  display: inline-block;
  font-size: 0;
  padding-top: 15px;
}

#navigation {
  position: absolute;
  right: 40px;
  bottom: 0px;
}

#menu-toggle {
  display: none;
  float: right;
}


/* HEADER > MENU */

#main-menu {
  float: right;
  font-size: 0;
  margin: 10px 0;
}

#main-menu>li {
  display: inline-block;
  margin-left: 30px;
  padding: 2px 0;
}

#main-menu>li.parent {
  background-image: url(../images/plus-gray.png);
  background-size: 7px 7px;
  background-repeat: no-repeat;
  background-position: left center;
}

#main-menu>li.parent>a {
  padding-left: 14px;
}

#main-menu>li>a {
  color: #eee;
  font-size: 14px;
  line-height: 14px;
  padding: 30px 0;
  text-decoration: none;
}

#main-menu>li:hover>a,
#main-menu>li.current-menu-item>a {
  color: #23dbdb;
}


/* HEADER > MENU > DROPDOWN */

#main-menu li {
  position: relative;
}

ul.sub-menu {
  /* level 2 */
  display: none;
  top: 38px;
  padding-top: 10px;
  position: absolute;
  width: 150px;
  z-index: 9999;
  right:0;
  left:initial;
}

ul.sub-menu ul.sub-menu {
  /* level 3+ */
  margin-top: -1px;
  padding-top: 0;
  right: 149px;
  top: 0px;
}

ul.sub-menu>li>a {
  background-color: #333;
  border: 1px solid #444;
  border-top: none;
  color: #bbb;
  display: block;
  font-size: 12px;
  line-height: 15px;
  padding: 10px 12px;
}

ul.sub-menu>li>a:hover {
  background-color: #2a2a2a;
  color: #fff;
}

ul.sub-menu>li:first-child {
  border-top: 3px solid #23dbdb;
}

ul.sub-menu ul.sub-menu>li:first-child {
  border-top: 1px solid #444;
}

ul.sub-menu>li:last-child>a {
  border-radius: 0 0 2px 2px;
}

ul.sub-menu>li>a.parent {
  background-image: url(../images/arrow.png);
  background-size: 5px 9px;
  background-repeat: no-repeat;
  background-position: 95% center;
}

#main-menu li:hover>ul.sub-menu {
  display: block;
  /* show the submenu */
}

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/2.2.3/jquery.min.js"></script>
<div id="wrap">
  <header>
    <div class="inner relative">
      <a class="logo" href="#"><img src="https://www.gravatar.com/avatar/851659509f07dd2fe27882da61f0da0a?s=64" alt="fresh design web"></a>
      <a id="menu-toggle" class="button dark" href="#"><i class="icon-reorder"></i></a>
      <nav id="navigation">
        <ul id="main-menu">
          <li class="current-menu-item"><a href="http://www.freshdesignweb.com">Home</a></li>
          <li class="parent">
            <a href="#">Features</a>
            <ul class="sub-menu">
              <li><a href="#"><i class="icon-wrench"></i> Elements</a></li>
              <li><a href="#"><i class="icon-credit-card"></i>  Pricing Tables</a></li>
              <li><a href="#"><i class="icon-gift"></i> Icons</a></li>
              <li>
                <a class="parent" href="#"><i class="icon-file-alt"></i> Pages</a>
                <ul class="sub-menu">
                  <li><a href="#">Full Width</a></li>
                  <li><a href="#">Left Sidebar</a></li>
                  <li><a href="#">Right Sidebar</a></li>
                  <li><a href="#">Double Sidebar</a></li>
                </ul>
              </li>
            </ul>
          </li>
          <li><a href="#">Portfolio</a></li>
          <li class="parent">
            <a href="#">Blog</a>
            <ul class="sub-menu">
              <li><a href="#">Large Image</a></li>
              <li><a href="#">Medium Image</a></li>
              <li><a href="#">Masonry</a></li>
              <li>
                <a class="parent" href="#"><i class="icon-file-alt"></i> Pages ></a>
                <ul class="sub-menu">
                  <li><a href="#">Full Width</a></li>
                  <li><a href="#">Left Sidebar</a></li>
                  <li><a href="#">Right Sidebar</a></li>
                  <li><a href="#">Double Sidebar</a></li>
                </ul>
              </li>
              <li><a href="#">Double Sidebar</a></li>
              <li><a href="#">Single Post</a></li>
            </ul>
          </li>
          <li><a href="#">Contact</a></li>
        </ul>
      </nav>
      <div class="clear"></div>
    </div>
  </header>