这个答案是不理想的，因为CSS flexbox和网格实现到CSS。然而，这仍然是一个可行的解决方案

在一个较小的屏幕上，你可能希望保持高度自动，因为col1, col2和col3是相互堆叠的。

然而，在媒体查询断点之后，您希望所有列的cols都以相同的高度紧挨着出现。

1125 px只是窗口宽度断点的一个例子，在此之后，您将希望将所有列设置为相同的高度。

<div class="wraper">
    <div class="col1">Lorem ipsum dolor sit amet.</div>
    <div class="col2">Lorem ipsum dolor sit amet, consectetur adipisicing elit. Eos laudantium, possimus sed, debitis amet in, explicabo dolor similique eligendi officia numquam eaque quae illo magnam distinctio odio, esse vero aspernatur.</div>
    <div class="col3">Lorem ipsum dolor sit amet, consectetur adipisicing elit. Dolorem, odio qui praesentium.</div>
</div>

当然，如果需要，还可以设置更多的断点。

<script>
    $(document).ready(function(){
        $(window).on('load resize', function() {
            let vraperH = $('.wraper').height();
            if (window.innerWidth>= 1125) {
              $('.col1').height(vraperH);
              $('.col2').height(vraperH);
              $('.col3').height(vraperH);
            }
            if (window.innerWidth < 1125) {
              $('.col1').height('auto');
              $('.col2').height('auto');
              $('.col3').height('auto');
            }
        });
    });
</script>

注意:此答案适用于不支持Flexbox标准的旧浏览器。有关现代方法，请参见:https://stackoverflow.com/a/23300532/1155721

我建议你看看跨浏览器CSS的等高列，没有黑客。

基本上，以浏览器兼容的方式使用CSS来实现这一点并不简单(但是对于表来说很简单)，所以请找到一个适当的预打包解决方案。

同样，答案也取决于你想要100%的高度还是相同的高度。通常都是等高的。如果是100%高，答案就略有不同。

如前所述，flexbox是最简单的。 如。

#main{ display: flex; align-items:center;}

这将使所有子元素对齐到父元素的中心。

我知道这个问题已经有很长一段时间了，但我找到了一个简单的解决方法，并且认为有人可以使用它(对不起，英语不好)。是这样的:

CSS

.main, .sidebar {
    float: none;
    padding: 20px;
    vertical-align: top;
}
.container {
    display: table;
}
.main {
    width: 400px;
    background-color: LightSlateGrey;
    display: table-cell;
}
.sidebar {
    width: 200px;
    display: table-cell;
    background-color: Tomato;
}

HTML

<div class="container clearfix">
    <div class="sidebar">
        simple text here
    </div>
    <div class="main">
        Lorem ipsum dolor sit amet, consectetur adipiscing elit. Etiam congue, tortor in mattis mattis, arcu erat pharetra orci, at vestibulum lorem ante a felis. Integer sit amet est ac elit vulputate lobortis. Vestibulum in ipsum nulla. Aenean erat elit, lacinia sit amet adipiscing quis, aliquet at erat. Vivamus massa sem, cursus vel semper non, dictum vitae mi. Donec sed bibendum ante.
    </div>
</div>

简单的例子。注意，您可以将其转换为响应性。

试着让最低利润率达到100%。

margin-bottom: 100%;

下面的代码提供了设置滚动div的最小高度的能力，并通过使用flex使其具有其父div的100%高度。

CSS:

.main {
  display: flex;
  flex-direction: column;
}

.scroll {
  overflow: auto;
  flex: 1 0 50px;
}

HTML:

<div class="main">
  <div class="scroll">
    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.
    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.
    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>