不要使用不透明度，使用rgba设置背景颜色，其中“a”是透明度级别。

所以不要:

background-color: rgb(0,0,255); opacity: 0.5;

use

background-color: rgba(0,0,255,0.5);

上面的答案对我来说似乎很复杂，所以我写了这个:

#kb-mask-overlay { background-color: rgba(0,0,0,0.8); width: 100%; height: 100%; z-index: 10000; top: 0; left: 0; position: fixed; content: ""; } #kb-mask-overlay > .pop-up { width: 800px; height: 150px; background-color: dimgray; margin-top: 30px; margin-left: 30px; } span { color: white; } <div id="kb-mask-overlay"> <div class="pop-up"> <span>Content of no opacity children</span> </div> </div> <div> <p> Lorem ipsum dolor sit amet, consectetur adipiscing elit. Proin vitae arcu nec velit pharetra consequat a quis sem. Vestibulum rutrum, ligula nec aliquam suscipit, sem justo accumsan mauris, id iaculis mauris arcu a eros. Donec sem urna, posuere id felis eget, pharetra rhoncus felis. Mauris tellus metus, rhoncus et laoreet sed, dictum nec orci. Mauris sagittis et nisl vitae aliquet. Sed vestibulum at orci ut tempor. Ut tristique vel erat sed efficitur. Vivamus vestibulum velit condimentum tristique lacinia. Sed dignissim iaculis mattis. Sed eu ligula felis. Mauris diam augue, rhoncus sed interdum nec, euismod eget urna. Morbi sem arcu, sollicitudin ut euismod ac, iaculis id dolor. Praesent ultricies eu massa eget varius. Nunc sit amet egestas arcu. Quisque at turpis lobortis nibh semper imperdiet vitae a neque. Proin maximus laoreet luctus. Nulla vel nulla ut elit blandit consequat. Nullam tempus purus vitae luctus fringilla. Nullam sodales vel justo vitae eleifend. Suspendisse et tortor nulla. Ut pharetra, sapien non porttitor pharetra, libero augue dictum purus, dignissim vehicula ligula nulla sed purus. Cras nec dapibus dolor. Donec nulla arcu, pretium ac ipsum vel, accumsan egestas urna. Vestibulum at bibendum tortor, a consequat eros. Nunc interdum at erat nec ultrices. Sed a augue sit amet lacus sodales eleifend ut id metus. Quisque vel luctus arcu. </p> </div>

Kb-mask-overlay是你的(不透明度)父母，弹出是你的(不透明度)孩子。它下面的所有内容都是站点的其余部分。

如果你的父类是透明的，并且你希望你的子类是相同的，但是是专门定义的(例如覆盖一个选择下拉菜单的用户代理样式)，有一个小技巧:

.parent {
     background-color: rgba(0,0,0,0.5);
}

.child {
     background-color: rgba(128,128,128,0);
}

其他人试图使一个表(或其他东西)看起来集中在一行使用不透明度。就像@Blowski说的，使用颜色而不是不透明度。看看这个小提琴:http://jsfiddle.net/2en6o43d/

.table:hover > .row:not(:hover)

我的答案不是关于静态的父子布局，而是关于动画。

I was doing an svg demo today, and i needed svg to be inside div (because svg is created with parent's div width and height, to animate the path around), and this parent div needed to be invisible during svg path animation (and then this div was supposed to animate opacity from 0 to 1, it's the most important part). And because parent div with opacity: 0 was hiding my svg, i came across this hack with visibility option (child with visibility: visible can be seen inside parent with visibility: hidden):

.main.invisible .test {
  visibility: hidden;
}
.main.opacity-zero .test {
  opacity: 0;
  transition: opacity 0s !important;
}
.test { // parent div
  transition: opacity 1s;
}
.test-svg { // child svg
  visibility: visible;
}

然后，在js中，你用timeout函数删除。invisible类，添加。opaque -zero类，用。style。top之类的东西触发布局;并删除。opaque - 0类。

var $main = $(".main");
  setTimeout(function() {
    $main.addClass('opacity-zero').removeClass("invisible");
    $(".test-svg").hide();
    $main.css("top");
    $main.removeClass("opacity-zero");
  }, 3000);

最好检查这个演示http://codepen.io/suez/pen/54bbb2f09e8d7680da1af2faa29a0aef?editors=011

如果你必须使用一个图像作为透明背景，你可以使用一个伪元素来解决它:

html

<div class="wrap"> 
   <p>I have 100% opacity</p>  
</div>

css

.wrap, .wrap > * {
  position: relative;
}
.wrap:before {
  content: " ";
  opacity: 0.2;
  background: url("http://placehold.it/100x100/FF0000") repeat;     
  position: absolute;
  width: 100%;
  height: 100%;
}