将div放在另一个div中，并设置父div的样式为position:relative;然后在子div上设置以下CSS属性:位置:绝对;底部:0;

另一种解决方案是明智地使用表和行span。通过设置前一行的所有表格单元格(除了主要内容外)为rowspan="2"，您将始终在您的主表格单元格的底部获得一个单元格孔，您可以始终放置valign="bottom"。

您还可以将其高度设置为一行所需的最小值。这样，不管剩下的文本占据了多少空间，你总是会在底部看到你最喜欢的一行文本。

我尝试了所有的div答案，我无法让他们做我需要的。

<table>
<tr>
   <td valign="top">
     this is just some random text
     <br> that should be a couple of lines long and
     <br> is at the top of where we need the bottom tag line
   </td>
   <td rowspan="2">
     this<br/>
     this<br/>
     this<br/>
     this<br/>
     this<br/>
     this<br/>
     this<br/>
     this<br/>
     this<br/>
     this<br/>
     this<br/>
     is really<br/>
     tall
  </td>
</tr>
<tr>
  <td valign="bottom">
      now this is the tagline we need on the bottom
  </td>
</tr>
</table>

浮动和绝对定位的组合对我来说很有用。我试图把消息的发送时间放在语音气泡的右下角。时间不应该与消息体重叠，除非真的有必要，否则它不会使气泡膨胀。

解决方案是这样的:

有两个跨度，文本完全相同; 一个漂浮着，但看不见; 另一个是绝对定位到角落;

不可见的浮动对象的目的是保证可见对象的空间。

.speech-bubble { font-size: 16px; max-width: 240px; margin: 10px; display: inline-block; background-color: #ccc; border-radius: 5px; padding: 5px; position: relative; } .inline-time { float: right; padding-left: 10px; color: red; } .giant-text { font-size: 36px; } .tremendous-giant-text { font-size: 72px; } .absolute-time { position: absolute; color: green; right: 5px; bottom: 5px; } .hidden { visibility: hidden; } <ul> <li> <span class='speech-bubble'> This text is supposed to wrap the time &lt;span&gt; which always seats at the corner of this bubble. <span class='inline-time'>13:55</span> </span> </li> <li> <span class='speech-bubble'> Absolute positioning doesn't work because it doesn't care if the two pieces of text overlap. We want to float. <span class='inline-time'>13:55</span> </span> </li> <li> <span class='speech-bubble'> Easy, uh? <span class='inline-time'>13:55</span> </span> </li> <li> <span class='speech-bubble'> Well, not <span class='giant-text'>THAT</span> easy <span class='inline-time'>13:56</span> </span> </li> <li> <span class='speech-bubble'> <span class='tremendous-giant-text'>See?</span> <span class='inline-time'>13:56</span> </span> </li> <li> <span class='speech-bubble'> The problem is, we can't tell the span to float to right AND bottom... <span class='inline-time'>13:56</span> </span> </li> <li> <span class='speech-bubble'> We can combinate float and absolute: use floated span to reserve space (the bubble will be inflated if necessary) so that the absoluted span is safe to go. <span class='inline-time'>13:56</span> </span> </li> <li> <span class='speech-bubble'> <span class='tremendous-giant-text'>See?</span> <span class='inline-time'>13:56</span> <span class='absolute-time'>13:56</span> </span> </li> <li> <span class='speech-bubble'> Make the floated span invisible. <span class='inline-time'>13:56</span> </span> </li> <li> <span class='speech-bubble'> <span class='tremendous-giant-text'>See?</span> <span class='inline-time hidden'>13:56</span> <span class='absolute-time'>13:56</span> </span> </li> <li> <span class='speech-bubble'> The giant text here is to simulate images which are common in a typical chat app. <span class='tremendous-giant-text'>Done!</span> <span class='inline-time hidden'>13:56</span> <span class='absolute-time'>13:56</span> </span> </li> </ul>

在与各种技巧斗争了几天之后，我不得不说这似乎是不可能的。即使使用javascript(我不想这样做)，这似乎是不可能的。

To clarify for those who may not have understood - this is what I am looking for: in publishing it is quite common to layout an inset (picture, table, figure, etc.) so that its bottom lines up with the bottom of the last line of text of a block (or page) with text flowing around the inset in a natural manner above and to the right or left depending on which side of the page the inset is on. In html/css it is trivial to use the float style to line up the top of an inset with the top of a block but to my surprise it appears impossible to line up the bottom of the text and inset despite it being a common layout task.

我想我将不得不重新审视这个项目的设计目标，除非有人有最后的建议。

通过一些JavaScript，我成功地将一个浮动元素固定在它的容器底部——并且仍然让它在文本中浮动，这对于像shape-outside这样的事情非常有用。

被浮动的元素得到一个margin-top赋值，它等于它的容器，减去它自己的高度。这将保留浮动，将元素推到其容器的底边，并防止文本在元素下面流动。

const resizeObserver = new ResizeObserver(entries => {
  if(entries.length == 0) return;
  const entry = entries[0];
  if(!entry.contentRect) return;

  const containerHeight = entry.contentRect.height;
  const imgHeight = imgElem.height;
  const imgOffset = containerHeight - imgHeight;
  
  imgElem.style.marginTop = imgOffset + 'px';
});

const imgElem = document.querySelector('.image');
resizeObserver.observe(imgElem.parentElement);

工作示例:https://codepen.io/strarsis/pen/QWGXGVy

多亏了ResizeObserver和对JavaScript的广泛支持，这似乎是一个非常可靠的解决方案。

如果你将父元素设置为position:relative，你可以将子元素设置为底部设置位置:absolute;和底部:0;

#{外 宽度:10 em; 高度:10 em; 背景颜色:蓝色; 位置:相对; ｝ #{内部 位置:绝对的; 底部:0; 背景颜色:白色; ｝ < div id = "外" > < div id = "内部" > <标题> < / h1 >完成 < / div > < / div >