css - 如何正确使用 z-index 来防止下拉菜单出现错误重叠？

Question

我找到了一个设计精美的下拉菜单 ( https://codepen.io/sammurphey/pen/BQvZbq )，我想在我的网站上使用它。不幸的是，下拉菜单在放置在彼此下方时会产生一些错误重叠。

这里用笔来描述问题:https://codepen.io/PLY51/pen/jXQKxR

这是相关的 CSS:

html, body {
  align-items: center;
  background: #e8e8e8;
  box-sizing: border-box;
  color: #666;
  cursor: default;
  font-family: sans-serif;
  height: 100%;
  justify-content: center;
  margin: 0;
  width: 100%;
  -webkit-tap-highlight-color: transparent;
  -webkit-touch-callout: none;
  -webkit-user-select: none;
  -moz-user-select: none;
  -ms-user-select: none;
  user-select: none;
}
* {
  box-sizing: inherit;
  cursor: inherit;
  transition-duration: 0.2s;
  transition-property: none;
  transition-timing-function: cubic-bezier(0.42, 0, 0.58, 1);
}
label.field {
  border-radius: 2px;
  color: #666;
  display: block;
  margin: 16px;
  max-width: 300px;
  padding: 8px;
  opacity: 0;
  position: relative;
  transition-property: opacity;
  z-index: 1;
}
label.field span {
  color: inherit;
  display: block;
  font-size: 16px;
  height: 20px;
  line-height: 20px;
  left: 9px;
  pointer-events: none;
  position: absolute;
  top: 32px;
  transform: scale(1) translateY(0);
  transition-property: color, font-size, top;
  z-index: 1;
}
label.field span.required::after {
  color: inherit;
  content: "*";
  display: block;
  height: 20px;
  left: -20px;
  line-height: 20px;
  position: absolute;
  text-align: center;
  top: 0;
  width: 20px;
}
.error label.field span {
  color: #f02318;
}
label.field .psuedo_select {
  background: rgba(255, 255, 255, 0);
  position: relative;
  border-color: #666;
  border-style: solid;
  border-width: 0 0 2px 0;
  color: #666;
  cursor: pointer;
  font-size: 20px;
  height: 24px;
  line-height: 24px;
  margin: 24px 32px 0 0;
  min-width: 250px;
  padding-top: 24px;
  outline: 0;
  z-index: 1;
}
label.field .psuedo_select::after {
  background: url("data:image/svg+xml;utf8,<svg fill='#666' height='24' viewBox='0 0 24 24' width='24' xmlns='http://www.w3.org/2000/svg'> <path d='M7.41 7.84L12 12.42l4.59-4.58L18 9.25l-6 6-6-6z'/> <path d='M0-.75h24v24H0z' fill='none'/> </svg>"), no-repeat;
  content: "";
  height: 24px;
  width: 24px;
  position: absolute;
  top: 0;
  right: 0;
  transition-property: background;
}
label.field .psuedo_select .selected {
  height: 24px;
  left: 1px;
  line-height: 24px;
  opacity: 0;
  position: absolute;
  top: 0;
  transform: translateY(24px);
  transition-property: opacity, transform;
  will-change: transform;
}
label.field .psuedo_select ul {
  background: #fff;
  box-shadow: 0 1px 4px 0 rgba(0, 0, 0, 0.14);
  display: block;
  height: 0;
  list-style: none;
  margin-top: 2px;
  opacity: 0;
  overflow: hidden;
  padding: 0 1px;
  pointer-events: none;
  transition-property: height, opacity;
  width: 100%;
  z-index: 2;
}
label.field .psuedo_select ul li {
  height: 32px;
  padding: 8px 4px;
}
label.field .deselect {
  height: 100vh;
  left: 0;
  position: fixed;
  top: 0;
  width: 100vw;
  z-index: -1;
}
label.field.focused {
  color: #007bed;
}
label.field.focused .psuedo_select {
  border-color: #007bed;
}
label.field.focused .psuedo_select::after {
  background: url("data:image/svg+xml;utf8,<svg fill='#007BED' height='24' viewBox='0 0 24 24' width='24' xmlns='http://www.w3.org/2000/svg'> <path d='M7.41 7.84L12 12.42l4.59-4.58L18 9.25l-6 6-6-6z'/> <path d='M0-.75h24v24H0z' fill='none'/> </svg>"), no-repeat;
}
label.field.focused .psuedo_select ul {
  opacity: 1;
  pointer-events: all;
}

如您所见，下拉菜单在单独放置(相当于底部下拉菜单)时工作正常，但如果您将另一个下拉菜单放在第一个下拉菜单下方，第一个下拉菜单的选项将与第二个下拉菜单重叠 buggy 的方式。

我知道 z-index 仅在元素具有 position 属性时才有效，并且需要考虑堆叠上下文，但不幸的是我对 CSS 不是很熟悉，如果有人能给我提示如何解决这个问题，我会很高兴问题。

感谢任何帮助。谢谢!

Answer 1

函数如下:

$('.psuedo_select').click(function()    {

$(".field").css("z-index", "1");
$(this).closest(".field").css("z-index", "2");

});