当我尝试点击它时，子菜单消失了

Question

我有以下菜单

#cssmenu {
  margin: 0;
  padding: 0;
  border: 0;
  list-style: none;
  line-height: 1;
  display: block;
  position: relative;
  -webkit-box-sizing: border-box;
  -moz-box-sizing: border-box;
  box-sizing: border-box;
  font-family: "Ubuntu", sans-serif;
  background: #14598e;
}

#cssmenu ul {
  margin: 0;
  padding: 0;
  border: 0;
  list-style: none;
  line-height: 1;
  display: block;
  position: relative;
  -webkit-box-sizing: border-box;
  -moz-box-sizing: border-box;
  box-sizing: border-box;
}

#cssmenu ul li {
  margin: 0;
  padding: 0;
  border: 0;
  list-style: none;
  line-height: 1;
  display: block;
  position: relative;
  -webkit-box-sizing: border-box;
  -moz-box-sizing: border-box;
  box-sizing: border-box;
}

#cssmenu ul li a {
  margin: 0;
  padding: 0;
  border: 0;
  list-style: none;
  line-height: 1;
  display: block;
  position: relative;
  -webkit-box-sizing: border-box;
  -moz-box-sizing: border-box;
  box-sizing: border-box;
}

#cssmenu #menu-button {
  margin: 0;
  padding: 0;
  border: 0;
  list-style: none;
  line-height: 1;
  display: block;
  position: relative;
  -webkit-box-sizing: border-box;
  -moz-box-sizing: border-box;
  box-sizing: border-box;
}

#cssmenu:after, #cssmenu > ul:after {
  content: ".";
  display: block;
  clear: both;
  visibility: hidden;
  line-height: 0;
  height: 0;
}

#cssmenu #menu-button {
  display: none;
}

#cssmenu > ul > li {
  float: left;
}

#cssmenu.align-center > ul {
  font-size: 0;
  text-align: center;
}

#cssmenu.align-center > ul > li {
  display: inline-block;
  float: none;
}

#cssmenu.align-center ul ul {
  text-align: left;
}

#cssmenu.align-right > ul > li {
  float: right;
}

#cssmenu > ul > li > a {
  padding: 17px;
  font-size: 16px;
  letter-spacing: 1px;
  text-decoration: none;
  color: #fff;
  text-transform: uppercase;
}

#cssmenu > ul > li:hover > a {
  background-color: #1d4f72;
}

#cssmenu > ul > li.has-sub > a {
  padding-right: 30px;
}

#cssmenu > ul > li.has-sub > a:after {
  position: absolute;
  top: 22px;
  right: 11px;
  width: 8px;
  height: 2px;
  display: block;
  background: #fff;
  content: "";
}

#cssmenu > ul > li.has-sub > a:before {
  position: absolute;
  top: 19px;
  right: 14px;
  display: block;
  width: 2px;
  height: 8px;
  background: #fff;
  content: "";
  -webkit-transition: all 0.25s ease;
  -moz-transition: all 0.25s ease;
  -ms-transition: all 0.25s ease;
  -o-transition: all 0.25s ease;
  transition: all 0.25s ease;
}

#cssmenu > ul > li.has-sub:hover > a:before {
  top: 23px;
  height: 0;
}

#cssmenu ul ul {
  position: absolute;
  left: -9999px;
}

#cssmenu.align-right ul ul {
  text-align: right;
}

#cssmenu ul ul li {
  height: 0;
  -webkit-transition: all 0.25s ease;
  -moz-transition: all 0.25s ease;
  -ms-transition: all 0.25s ease;
  -o-transition: all 0.25s ease;
  transition: all 0.25s ease;
}

#cssmenu li:hover > ul {
  left: auto;
}

#cssmenu.align-right li:hover > ul {
  left: auto;
  right: 0;
}

#cssmenu li:hover > ul > li {
  height: 60px;
}

#cssmenu ul ul li a {
  border-bottom: 1px solid rgba(150, 150, 150, 0.15);
  padding: 20px 30px 35px 15px;
  width: 260px;
  font-size: 13px;
  text-decoration: none;
  color: #fff;
  background: #14598e;
  text-transform: uppercase;
}

#cssmenu ul li ul li:hover > a {
  background-color: #1d4f72;
}

<div class="content">
  <div id='cssmenu'>
    <ul>
      <li><a href='inicio.html'>Inicio</a></li>
      <li class='active'><a href='#'>Soluciones</a>
        <ul>
          <li><a href='solucion1.html'>Solución 1</a></li>
          <li><a href='solucion2.html'>Solución 2</a></li>
          <li><a href='solucion3.html'>Solución 3</a></li>
        </ul>
      </li>
      <li><a href='beneficios.html'>Beneficios</a></li>
      <li><a href='cliente.html'>Clientes</a></li>
      <li><a href='empleo.html'>Empleos</a></li>
      <li><a href='#'>Blog</a></li>
    </ul>
  </div>
</div>

我遇到的问题是，当 window 的大小正常时，子菜单显示正确，并且可以 select 它具有的任何选项。但是，当我将 window 的尺寸缩小几厘米时，会显示子菜单，但当我尝试 select 某些选项时，它会立即消失。我已经查看了代码，但没有看到该行为的原因，我希望并且可以帮助我找到问题所在。提前非常感谢...

Answer 1

如果我理解你的话，当你的菜单显示在两行时，你就有问题了。您可以添加：

#cssmenu ul ul {
    z-index: 10;
}

这样，您的子菜单将位于您的菜单上方，您将能够点击这些项目。

   #cssmenu {
      margin: 0;
      padding: 0;
      border: 0;
      list-style: none;
      line-height: 1;
      display: block;
      position: relative;
      -webkit-box-sizing: border-box;
      -moz-box-sizing: border-box;
      box-sizing: border-box;
      font-family: "Ubuntu", sans-serif;
      background: #14598e;
    }

    #cssmenu ul {
      margin: 0;
      padding: 0;
      border: 0;
      list-style: none;
      line-height: 1;
      display: block;
      position: relative;
      -webkit-box-sizing: border-box;
      -moz-box-sizing: border-box;
      box-sizing: border-box;
    }

    #cssmenu ul li {
      margin: 0;
      padding: 0;
      border: 0;
      list-style: none;
      line-height: 1;
      display: block;
      position: relative;
      -webkit-box-sizing: border-box;
      -moz-box-sizing: border-box;
       box-sizing: border-box;
    }

    #cssmenu ul li a {
      margin: 0;
      padding: 0;
      border: 0;
      list-style: none;
      line-height: 1;
      display: block;
      position: relative;
      -webkit-box-sizing: border-box;
      -moz-box-sizing: border-box;
      box-sizing: border-box;
    }

    #cssmenu #menu-button {
      margin: 0;
      padding: 0;
      border: 0;
      list-style: none;
      line-height: 1;
      display: block;
      position: relative;
      -webkit-box-sizing: border-box;
      -moz-box-sizing: border-box;
      box-sizing: border-box;
    }

    #cssmenu:after, #cssmenu > ul:after {
      content: ".";
      display: block;
      clear: both;
      visibility: hidden;
      line-height: 0;
      height: 0;
    }

    #cssmenu #menu-button {
      display: none;
    }

    #cssmenu > ul > li {
      float: left;
    }

    #cssmenu.align-center > ul {
      font-size: 0;
      text-align: center;
    }

    #cssmenu.align-center > ul > li {
      display: inline-block;
      float: none;
    }

    #cssmenu.align-center ul ul {
      text-align: left;
    }

    #cssmenu.align-right > ul > li {
      float: right;
    }

    #cssmenu > ul > li > a {
      padding: 17px;
      font-size: 16px;
      letter-spacing: 1px;
      text-decoration: none;
      color: #fff;
      text-transform: uppercase;
    }

    #cssmenu > ul > li:hover > a {
      background-color: #1d4f72;
    }

    #cssmenu > ul > li.has-sub > a {
      padding-right: 30px;
    }

    #cssmenu > ul > li.has-sub > a:after {
      position: absolute;
      top: 22px;
      right: 11px;
      width: 8px;
      height: 2px;
      display: block;
      background: #fff;
      content: "";
    }

    #cssmenu > ul > li.has-sub > a:before {
      position: absolute;
      top: 19px;
      right: 14px;
      display: block;
      width: 2px;
      height: 8px;
      background: #fff;
      content: "";
      -webkit-transition: all 0.25s ease;
      -moz-transition: all 0.25s ease;
      -ms-transition: all 0.25s ease;
      -o-transition: all 0.25s ease;
      transition: all 0.25s ease;
    }

    #cssmenu > ul > li.has-sub:hover > a:before {
      top: 23px;
      height: 0;
    }

    #cssmenu ul ul {
      position: absolute;
      z-index:10;
      left: -9999px;
    }

    #cssmenu.align-right ul ul {
      text-align: right;
    }

    #cssmenu ul ul li {
      height: 0;
      -webkit-transition: all 0.25s ease;
      -moz-transition: all 0.25s ease;
      -ms-transition: all 0.25s ease;
      -o-transition: all 0.25s ease;
      transition: all 0.25s ease;
    }

    #cssmenu li:hover > ul {
      left: auto;
    }

    #cssmenu.align-right li:hover > ul {
      left: auto;
      right: 0;
    }

    #cssmenu li:hover > ul > li {
      height: 60px;
    }

    #cssmenu ul ul li a {
      border-bottom: 1px solid rgba(150, 150, 150, 0.15);
      padding: 20px 30px 35px 15px;
      width: 260px;
      font-size: 13px;
      text-decoration: none;
      color: #fff;
      background: #14598e;
      text-transform: uppercase;
    }

    #cssmenu ul li ul li:hover> a {
      background-color: #1d4f72;
    }

    <div class="content">
      <div id='cssmenu'>
        <ul><li><a href='inicio.html'>Inicio</a></li>
          <li class='active'><a href='#'>Soluciones</a>
            <ul><li><a href='solucion1.html'>Solución 1</a></li>
              <li><a href='solucion2.html'>Solución 2</a></li>
              <li><a href='solucion3.html'>Solución 3</a></li></ul></li>
         <li><a href='beneficios.html'>Beneficios</a></li>
          <li><a href='cliente.html'>Clientes</a></li>
          <li><a href='empleo.html'>Empleos</a></li>
          <li><a href='#'>Blog</a></li></ul></div></div>

Answer 2

当您 :hover 将该元素及其任何子项置于菜单中其余链接之上时，您只需要 li 上的 z-index: 1。

#cssmenu {
  margin: 0;
  padding: 0;
  border: 0;
  list-style: none;
  line-height: 1;
  display: block;
  position: relative;
  -webkit-box-sizing: border-box;
  -moz-box-sizing: border-box;
  box-sizing: border-box;
  font-family: "Ubuntu", sans-serif;
  background: #14598e;
}

#cssmenu ul {
  margin: 0;
  padding: 0;
  border: 0;
  list-style: none;
  line-height: 1;
  display: block;
  position: relative;
  -webkit-box-sizing: border-box;
  -moz-box-sizing: border-box;
  box-sizing: border-box;
}

#cssmenu ul li {
  margin: 0;
  padding: 0;
  border: 0;
  list-style: none;
  line-height: 1;
  display: block;
  position: relative;
  -webkit-box-sizing: border-box;
  -moz-box-sizing: border-box;
  box-sizing: border-box;
}

#cssmenu ul li a {
  margin: 0;
  padding: 0;
  border: 0;
  list-style: none;
  line-height: 1;
  display: block;
  position: relative;
  -webkit-box-sizing: border-box;
  -moz-box-sizing: border-box;
  box-sizing: border-box;
}

#cssmenu #menu-button {
  margin: 0;
  padding: 0;
  border: 0;
  list-style: none;
  line-height: 1;
  display: block;
  position: relative;
  -webkit-box-sizing: border-box;
  -moz-box-sizing: border-box;
  box-sizing: border-box;
}

#cssmenu:after, #cssmenu > ul:after {
  content: ".";
  display: block;
  clear: both;
  visibility: hidden;
  line-height: 0;
  height: 0;
}

#cssmenu #menu-button {
  display: none;
}

#cssmenu > ul > li {
  float: left;
}

#cssmenu.align-center > ul {
  font-size: 0;
  text-align: center;
}

#cssmenu.align-center > ul > li {
  display: inline-block;
  float: none;
}

#cssmenu.align-center ul ul {
  text-align: left;
}

#cssmenu.align-right > ul > li {
  float: right;
}

#cssmenu > ul > li > a {
  padding: 17px;
  font-size: 16px;
  letter-spacing: 1px;
  text-decoration: none;
  color: #fff;
  text-transform: uppercase;
}

#cssmenu > ul > li:hover {
  z-index: 1;
}

#cssmenu > ul > li:hover > a {
  background-color: #1d4f72;
}

#cssmenu > ul > li.has-sub > a {
  padding-right: 30px;
}

#cssmenu > ul > li.has-sub > a:after {
  position: absolute;
  top: 22px;
  right: 11px;
  width: 8px;
  height: 2px;
  display: block;
  background: #fff;
  content: "";
}

#cssmenu > ul > li.has-sub > a:before {
  position: absolute;
  top: 19px;
  right: 14px;
  display: block;
  width: 2px;
  height: 8px;
  background: #fff;
  content: "";
  -webkit-transition: all 0.25s ease;
  -moz-transition: all 0.25s ease;
  -ms-transition: all 0.25s ease;
  -o-transition: all 0.25s ease;
  transition: all 0.25s ease;
}

#cssmenu > ul > li.has-sub:hover > a:before {
  top: 23px;
  height: 0;
}

#cssmenu ul ul {
  position: absolute;
  left: -9999px;
}

#cssmenu.align-right ul ul {
  text-align: right;
}

#cssmenu ul ul li {
  height: 0;
  -webkit-transition: all 0.25s ease;
  -moz-transition: all 0.25s ease;
  -ms-transition: all 0.25s ease;
  -o-transition: all 0.25s ease;
  transition: all 0.25s ease;
}

#cssmenu li:hover > ul {
  left: auto;
}

#cssmenu.align-right li:hover > ul {
  left: auto;
  right: 0;
}

#cssmenu li:hover > ul > li {
  height: 60px;
}

#cssmenu ul ul li a {
  border-bottom: 1px solid rgba(150, 150, 150, 0.15);
  padding: 20px 30px 35px 15px;
  width: 260px;
  font-size: 13px;
  text-decoration: none;
  color: #fff;
  background: #14598e;
  text-transform: uppercase;
}

#cssmenu ul li ul li:hover > a {
  background-color: #1d4f72;
}

<div class="content">
  <div id='cssmenu'>
    <ul>
      <li><a href='inicio.html'>Inicio</a></li>
      <li class='active'><a href='#'>Soluciones</a>
        <ul>
          <li><a href='solucion1.html'>Solución 1</a></li>
          <li><a href='solucion2.html'>Solución 2</a></li>
          <li><a href='solucion3.html'>Solución 3</a></li>
        </ul>
      </li>
      <li><a href='beneficios.html'>Beneficios</a></li>
      <li><a href='cliente.html'>Clientes</a></li>
      <li><a href='empleo.html'>Empleos</a></li>
      <li><a href='#'>Blog</a></li>
    </ul>
  </div>
</div>

Answer 3

添加 z-index 将指定元素如何在视觉上堆叠。具有较大 z-index 的元素将具有较大的堆栈顺序，并且将始终堆栈在具有较低堆栈顺序的元素之前。

#cssmenu ul ul {
  position: absolute;
  z-index: 1;
  left: -9999px;
}

Blockquote Note z-index only works on positioned elements (position:absolute, position:relative, or position:fixed)

当我尝试点击它时，子菜单消失了

submenu disappears when I try to click on it

html

css

submenu