保持一个绝对定位的 HTML 元素在它的位置

Question

具有position: absolute的 span 标记red arrow按预期位于右下角。 当我开始在content容器中输入文本时，箭头开始飘走。

将content高度设置为auto或100%并没有解决问题。

无论content元素的高度如何，我们如何保持span标签red arrow固定在右下角？

https://codesandbox.io/s/gracious-shockley-dcp59?file=/src/App.js

HTML

<div className="App">
      <div className="container">
        <div className="content">
          <div suppressContentEditableWarning={true} contentEditable="true">
            Test
          </div>
        </div>
        <span className="helper"></span>
      </div>

      <div className="container">
        <div className="content">
          <div suppressContentEditableWarning={true} contentEditable="true">
            <p>
              Lorem Ipsum is simply dummy text of the printing and typesetting
              industry. Lorem Ipsum has been the industry's standard dummy text
              ever since the 1500s, when an unknown printer took a galley of
              type and scrambled it to make a type specimen book. It has
              survived not only five centuries, but also the leap into
              electronic typesetting, remaining essentially unchanged. It was
              popularised in the 1960s with the release of Letraset sheets
              containing Lorem Ipsum passages, and more recently with desktop
              publishing software like Aldus PageMaker including versions of
              Lorem Ipsum.
            </p>
          </div>
        </div>
        <span className="helper"></span>
      </div>
    </div>

样式文件

.container {
  overflow: auto;
  border: 1px solid #000;
  width: 150px;
  height: 100px;
  float: left;
  transform: translate(0px, 10px);
  margin-right: 20px;
}

.content {
  padding: 15px;
  background-color: #ddd;
}

.helper::before {
  content: "";
  position: absolute;
  right: 3px;
  bottom: 3px;
  width: 5px;
  height: 5px;
  border-right: 4px solid red;
  border-bottom: 4px solid red;
}

Answer 1

为了解决这个问题，我将滚动行为定义移动到.content并分配position: relative; 到.container 。

 .container { position: relative; /* new */ overflow: hidden; /* changed */ border: 1px solid #000; width: 150px; height: 100px; float: left; transform: translate(0px, 10px); margin-right: 20px; } .content { padding: 15px; background-color: #ddd; width: inherit; /* new */ height: inherit; /* new */ box-sizing: border-box; /* new */ overflow-y: scroll; /* new */ } .helper { position: absolute; right: 3px; bottom: 3px; width: 5px; height: 5px; border-right: 4px solid red; border-bottom: 4px solid red; }

 <div class="App"> <div class="container"> <div class="content"> <div suppressContentEditableWarning={true} contentEditable="true"> Test </div> </div> <span class="helper"></span> </div> <div class="container"> <div class="content"> <div suppressContentEditableWarning={true} contentEditable="true"> Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book. It has survived not only five centuries, but also the leap into electronic typesetting, remaining essentially unchanged. It was popularised in the 1960s with the release of Letraset sheets containing Lorem Ipsum passages, and more recently with desktop publishing software like Aldus PageMaker including versions of Lorem Ipsum. </div> </div> <span class="helper"></span> </div> </div>

注意：我已将className更改为class以使代码片段起作用。 我没有对 HTML 结构进行任何更改。

Answer 2

您的助手 div 位于错误的位置。 它需要在.content div 中，并且.content div 需要有position: relative 。 现在助手是相对于父容器的，而不是内容。 此外，您不需要为辅助形状使用伪元素，这些样式可以直接应用于元素和content: ""已删除。

HTML

 <div className="App">
  <div className="container">
    <div className="content">
      <div suppressContentEditableWarning={true} contentEditable="true">
        Test
      </div>
      <span className="helper"></span>
    </div>
  </div>

  <div className="container">
    <div className="content">
      <div suppressContentEditableWarning={true} contentEditable="true">
        <p>
          Lorem Ipsum is simply dummy text of the printing and typesetting
          industry. Lorem Ipsum has been the industry's standard dummy text
          ever since the 1500s, when an unknown printer took a galley of
          type and scrambled it to make a type specimen book. It has
          survived not only five centuries, but also the leap into
          electronic typesetting, remaining essentially unchanged. It was
          popularised in the 1960s with the release of Letraset sheets
          containing Lorem Ipsum passages, and more recently with desktop
          publishing software like Aldus PageMaker including versions of
          Lorem Ipsum.
        </p>
      </div>
      <span className="helper"></span>
    </div>
  </div>
</div>

样式文件

.App {
  font-family: sans-serif;
}

.container {
  overflow: auto;
  border: 1px solid #000;
  width: 150px;
  height: 100px;
  float: left;
  transform: translate(0px, 10px);
  margin-right: 20px;
}

.content {
  padding: 15px;
  background-color: #ddd;
}
.content {
  position: relative;
}
.helper {
  position: absolute;
  right: 3px;
  bottom: 3px;
  width: 5px;
  height: 5px;
  border-right: 4px solid red;
  border-bottom: 4px solid red;
}