使元素粘在div的底部

Question

以下代码生成一组蓝框，在其中两个框中显示一个小白框。如何将这些白色盒子贴在蓝色盒子的底部？我尝试将margin-top: auto;添加到.test，但这不起作用。

.flex-container {
    display: -webkit-flex;
    display: flex;
    width: 400px;
    height: 250px;
    background-color: lightgrey;
    flex-wrap: wrap;
}

.flex-item {
    background-color: cornflowerblue;
    width: 100px;
    height: 100px;
    margin: 10px;
}

.test {
    background-color: white;
    width: 20px;
    height: 20px;
    margin-bottom: 0 auto;
}

<div class="flex-container">
  <div class="flex-item">flex item 1flex item 1flex item 1flex item 1flex 
  item 1<div class="test"></div></div>
  <div class="flex-item">flex item 2<div class="test"></div></div>
  <div class="flex-item">flex item 3</div>
  <div class="flex-item">flex item 3</div>  
  <div class="flex-item">flex item 3</div>  
</div>

Answer 1

只需编辑您的CSS并将// Call on a random style ID to display in rating window. $resultSet = $conn->query("SELECT pictureID,userID FROM styles ORDER BY RAND() LIMIT 1"); while($rows = $resultSet->fetch_assoc() ){ $rateableUserID = $rows['userID']; $rateablePictureID = $rows['pictureID']; } 添加到＆＃39; flex-item， 和position: relative到＆＃39;测试＆＃39;。 当然，您必须添加position: absolute才能将其发送到底部

bottom: 0px

Answer 2

将position: absolute;和bottom: 0;添加到.test多维数据集（您还可以添加left: 0，但这仍然是默认值），并position: relative;到其容器让他们成为孩子绝对地位的“锚”。

.flex-container {
  display: -webkit-flex;
  display: flex;
  width: 400px;
  height: 250px;
  background-color: lightgrey;
  flex-wrap: wrap;
}

.flex-item {
  background-color: cornflowerblue;
  width: 100px;
  height: 100px;
  margin: 10px;
  position: relative;;
}

.test {
  background-color: white;
  width: 20px;
  height: 20px;
  position: absolute;
  bottom: 0;
}

<div class="flex-container">
  <div class="flex-item">flex item 1flex item 1flex item 1flex item 1flex item 1
    <div class="test"></div>
  </div>
  <div class="flex-item">flex item 2
    <div class="test"></div>
  </div>
  <div class="flex-item">flex item 3</div>
  <div class="flex-item">flex item 3</div>
  <div class="flex-item">flex item 3</div>
</div>

评论后的补充：

在评论中说出其他问题：

您可以使用flex-direction: column将弹性项目定义为弹性容器，并将margin-top: auto应用于.test。但是，您需要将height flex-item更改为min-height才能允许其展开：

.flex-container {
  display: -webkit-flex;
  display: flex;
  width: 400px;
  height: 250px;
  background-color: lightgrey;
  flex-wrap: wrap;
}

.flex-item {
  background-color: cornflowerblue;
  width: 100px;
  min-height: 100px;
  margin: 10px;
  display: flex;
  flex-direction: column;
}

.test {
  background-color: white;
  width: 20px;
  height: 50px;
  margin-top: auto;
}

<div class="flex-container">
  <div class="flex-item">flex item 1flex item 1flex item 1flex item 1flex item 1
    <div class="test"></div>
  </div>
  <div class="flex-item">flex item 2
    <div class="test"></div>
  </div>
  <div class="flex-item">flex item 3</div>
  <div class="flex-item">flex item 3</div>
  <div class="flex-item">flex item 3</div>
</div>

Answer 3

margin如果父级也是一个弹性框 （同样如果margin-x有一个值）

此处： margin:auto 0 0;应该这样做。

（margin:auto 0 0 auto ;会将其设置在右下角）

＆＃13;

＆＃13;

.flex-container {
    display: -webkit-flex;
    display: flex;
    width: 400px;
    height: 250px;
    background-color: lightgrey;
    flex-wrap: wrap;
}

.flex-item {
    background-color: cornflowerblue;
    width: 100px;
    height: 100px;
    margin: 10px;
        display: -webkit-flex;
    display: flex;
    flex-direction:column;
}

.test {
    background-color: white;
    width: 20px;
    height: 20px;
    margin-top:auto;
    margin-bottom: 0;
}

＆＃13;

<div class="flex-container">
  <div class="flex-item">flex item 1flex item 1flex item 1flex item 1flex 
  item 1<div class="test"></div></div>
  <div class="flex-item">flex item 2<div class="test"></div></div>
  <div class="flex-item">flex item 3</div>
  <div class="flex-item">flex item 3</div>  
  <div class="flex-item">flex item 3</div>  
</div>

＆＃13;

＆＃13;

＆＃13;

Answer 4

您可以直接在弹性儿童身上使用align-self。

.container {
  display: flex;
}

.place-at-bottom {
  align-self: flex-end;
}


/* ignore them */
.container {
  width: 200px;
  height: 200px;
  background: yellow;
}

.place-at-bottom {
  width: 50px;
  height: 50px;
  background: cyan;
  border: 1px solid black;
}

<div class="container">

  <div class="place-at-bottom"></div>
</div>