CSS animation-fill-mode 和 z-index 问题

Question

我在我正在处理的元素中使用 CSS 动画(来自 animate.css)。 我发现，当在一个容器中淡入一个绝对定位且 z-indexed 的子元素时，子元素的 z-index 没有正常工作。

我在这个 fiddle 中重现了这个问题: http://jsfiddle.net/Lxsf9ako/

问题似乎是由

引起的

animation-fill-mode: both;

这个样式是由 animate.css 放置在容器上的，因此我无法控制它。我可以使用 animation-fill-mode: none 覆盖它，但我不想对每个动画都这样做。

对此有什么想法吗？

更新: 我刚刚发现这是与 webkit 相关的，IE11 可以正确呈现它。

更新 2: 我无法在悬停时编辑 .container 类。

更新 3: Fiddle 中的“悬停”只是一个演示。事实上，.over 对象是来自 angular-ui-bootstrap datepicker 指令的弹出窗口，而 .container 元素是整个应用程序中使用的通用元素。给它们一个额外的 id/class 以将它们标识为 datepicker 容器对我来说不是一个干净的解决方案。

Answer 1

只需添加

#hoverme{
   z-index: 1;
}

DEMO

为什么你必须这样做

Without any z-index value, elements stack in the order that they appear in the DOM (the lowest one down at the same hierarchy level appears on top). Elements with non-static positioning will always appear on top of elements with default static positioning.

Also note that nesting plays a big role. If an element B sits on top of element A, a child element of element A can never be higher than element B.

From css-tricks.com

#hoverme {
  z-index: 1;
}
.container {
  background: rgb(255, 255, 255);
  /* Old browsers */
  background: -webkit-gradient(linear, 0 0, 0 100%, from(#fff), to(#efefef));
  background: -webkit-linear-gradient(#fff 0%, #efefef 100%);
  background: -moz-linear-gradient(#fff 0%, #efefef 100%);
  background: -o-linear-gradient(#fff 0%, #efefef 100%);
  background: linear-gradient(#fff 0%, #efefef 100%);
  filter: progid: DXImageTransform.Microsoft.gradient(startColorstr='#ffffff', endColorstr='#efefef', GradientType=0);
  /* IE6-9 */
  font-family: 'Helvetica Neue', Helvetica, Arial, sans-serif;
  display: block;
  width: 100%;
  border: 1px solid #c7c7c7;
  margin-bottom: 10px;
  position: relative;
  padding: 20px;
  box-sizing: border-box;
  -webkit-animation-name: fadeIn;
  /* Safari, Chrome and Opera > 12.1 */
  -moz-animation-name: fadeIn;
  /* Firefox < 16 */
  -ms-animation-name: fadeIn;
  /* Internet Explorer */
  -o-animation-name: fadeIn;
  /* Opera < 12.1 */
  animation-name: fadeIn;
  -webkit-animation-duration: 1s;
  -moz-animation-duration: 1s;
  -ms-animation-duration: 1s;
  -o-animation-duration: 1s;
  animation-duration: 1s;
  -webkit-animation-fill-mode: both;
  -moz-animation-fill-mode: both;
  -ms-animation-fill-mode: both;
  -o-animation-fill-mode: both;
  animation-fill-mode: both;
}
#hoverme .over {
  display: none;
  padding: 20px;
  position: absolute;
  top: 20px;
  left: 20px;
  width: 200px;
  background: #efefef;
  z-index: 10;
  box-sizing: border-box;
  -webkit-box-shadow: 2px 2px 4px 0px rgba(0, 0, 0, 0.75);
  -moz-box-shadow: 2px 2px 4px 0px rgba(0, 0, 0, 0.75);
  box-shadow: 2px 2px 4px 0px rgba(0, 0, 0, 0.75);
}
#hoverme:hover .over {
  display: block;
}
@keyframes fadeIn {
  0% {
    opacity: 0;
  }
  100% {
    opacity: 1;
  }
}
/* Firefox < 16 */

@-moz-keyframes fadeIn {
  0% {
    opacity: 0;
  }
  100% {
    opacity: 1;
  }
}
/* Safari, Chrome and Opera > 12.1 */

@-webkit-keyframes fadeIn {
  0% {
    opacity: 0;
  }
  100% {
    opacity: 1;
  }
}
/* Internet Explorer */

@-ms-keyframes fadeIn {
  0% {
    opacity: 0;
  }
  100% {
    opacity: 1;
  }
}
/* Opera < 12.1 */

@-o-keyframes fadeIn {
  0% {
    opacity: 0;
  }
  100% {
    opacity: 1;
  }
}

<div id="hoverme" class="container">
  <div class="over">I should be over the next container</div>
</div>
<div class="container">I should be under the .over</div>

更新

您还可以在 .over 上使用具有 opacity 和 visibility 的过渡。

#hoverme .over {
    opacity: 0; 
    visibility:hidden;
    transition:visibility 0.4s, opacity 0.4s; 
    ...
}

#hoverme:hover .over {
    visibility:visible;
    opacity:1;
}

DEMO

.container {
  background: rgb(255, 255, 255);
  /* Old browsers */
  background: -webkit-gradient(linear, 0 0, 0 100%, from(#fff), to(#efefef));
  background: -webkit-linear-gradient(#fff 0%, #efefef 100%);
  background: -moz-linear-gradient(#fff 0%, #efefef 100%);
  background: -o-linear-gradient(#fff 0%, #efefef 100%);
  background: linear-gradient(#fff 0%, #efefef 100%);
  filter: progid: DXImageTransform.Microsoft.gradient(startColorstr='#ffffff', endColorstr='#efefef', GradientType=0);
  /* IE6-9 */
  font-family: 'Helvetica Neue', Helvetica, Arial, sans-serif;
  display: block;
  width: 100%;
  border: 1px solid #c7c7c7;
  margin-bottom: 10px;
  position: relative;
  padding: 20px;
  box-sizing: border-box;
}
#hoverme .over {
  opacity: 0;
  visibility: hidden;
  transition: visibility 0.4s, opacity 0.4s;
  padding: 20px;
  position: absolute;
  top: 20px;
  left: 20px;
  width: 200px;
  background: #efefef;
  z-index: 10;
  box-sizing: border-box;
  -webkit-box-shadow: 2px 2px 4px 0px rgba(0, 0, 0, 0.75);
  -moz-box-shadow: 2px 2px 4px 0px rgba(0, 0, 0, 0.75);
  box-shadow: 2px 2px 4px 0px rgba(0, 0, 0, 0.75);
}
#hoverme:hover .over {
  visibility: visible;
  opacity: 1;
}

<div id="hoverme" class="container">
  <div class="over">I should be over the next container</div>
</div>
<div class="container">I should be under the .over</div>