子div的高度溢出父容器 [英] Height of child div overflows parent container

问题描述

我们需要为div的溢出文本设置垂直滚动条.问题是，当我们将高度设置为100％并溢出为auto时，由于它前面有另一个同级div，它会扩展到其父容器之外.这是一个示例:

We need to instate a vertical scrollbar for overflow text of a div. The problem is when we set the height to 100% and overflow to auto, it expands beyond its parent container because of another sibling div preceding it. Here is an example:

<style type="text/css">
    .container {height: 100px; width: 100px; border: solid;}
    .titlebar {height: 2em; background: gray;}
    .app-body {height: 100%; overflow: auto; background: lightblue;}    
</style>

...

<div class="container">
    <div class="titlebar"></div>
    <div class="app-body">Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Donec condimentum pretium nisl.</div>
</div>

app-body 设置为100％会导致其高度为100px，从而使其超出 container 的底部超出 2em .我们尝试完全不对 app-body 使用高度，但这会导致高度溢出而不显示滚动条.

app-body set to 100% causes it to have a height of 100px which makes it overflow beyond the bottom of container by 2em. We tried not using a height at all for app-body but that causes it to overflow without the scrollbar displayed.

我知道我们可以将高度设置为较小的百分比或固定的像素数，但是如果字体大小更改，这会对我们造成问题.如果 100％-2em 的高度有效，那将是我们试图定义的有效高度.

I know we could set the height to a smaller percentage or a fixed number of pixels but that will cause problems for us if the font size changes. If a height of 100% - 2em was valid then that would be effectively what we are trying to define.

推荐答案

尝试一下，将app-body位置设置为绝对，然后将顶部固定为3em，其余固定为0:

Try this, setting the app-body positioning to absolute and then fixed the top to 3em and the rest to 0:

<style type="text/css">
  .container {height: 100px; width: 100px; border: solid; 
      position: relative;}
  .titlebar {height: 2em; background: gray; 
      position: relative;}
  .app-body {height: auto; overflow: auto; background: lightblue; 
      position: absolute; top: 2em; left: 0; right: 0; bottom: 0;}    
</style>

PS:经过FF3.6，IE8，Webkit浏览器的测试.

PS: Above tested on FF3.6, IE8, Webkit browsers.

这篇关于子div的高度溢出父容器的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！