Bootstrap-4 模态页脚中的可滚动文本区域

Question

我在我的 Angular-6 项目中使用 Bootstrap-4 模态。 对于modal，Modal-Header是固定高度，Modal-Body是可滚动的，Modal-Footer是可变高度但不能滚动的。

以下是我的基本 HTML：

/*for debugging purpose*/
.modal {
  display: block !important;
}

.modal-footer {
  display: flex;
  align-items: center;
  justify-content: flex-end;
  border-color: #e0e0e7;
  padding: 15px 20px 15px 55px;
  min-height: 70px;
  border-top: 1px solid #e9ecef;
}

.comment-input {
  position: relative;
  width: 100%;
  min-height: 40px;
}

.textarea {
  max-height: 80px;
  overflow: auto;
  width: 100%;
  min-height: 40px;
  padding: 10px 10px 10px 16px;
  word-wrap: break-word;
  line-height: 20px;
}

.textarea:empty:not(:focus)::before {
  content: 'Type your comments here';
  position: absolute;
}

<link href="https://stackpath.bootstrapcdn.com/bootstrap/4.1.3/css/bootstrap.min.css" rel="stylesheet" />
<div class="modal" role="dialog">
  <div class="modal-dialog">
    <div class="modal-content">
      <div class="modal-header"></div>
      <div class="modal-body"></div>
      <div class="modal-footer">
        <div class="comment-input">
          <div class="textarea" contenteditable="true"></div>
        </div>
      </div>
    </div>
  </div>
</div>

我试图在插入四行文本后使我的 textarea 可滚动。在插入四行文本之前，modal-footer 应该随着 textarea 的增长而增加其高度。我试图通过上面的 HTML 和 CSS 来做同样的事情，但不知何故 modal-footer 并没有因为 textarea 的高度而增加。每一个可能的解决方案将不胜感激。谢谢。

Answer 1

对于modal body，您需要设置max-height 和overflow-y: scroll 属性，以便在内容结束时滚动max-height。

.modal-body {
  max-height: 200px;
  overflow-y: scroll;
}

modal footer 则相反，需要去掉文本区的max-height 以及.textarea 的overflow:auto 属性

/*for debugging purpose*/

.modal {
  display: block !important;
}

.modal-footer {
  display: flex;
  align-items: center;
  justify-content: flex-end;
  border-color: #e0e0e7;
  padding: 15px 20px 15px 55px;
  min-height: 70px;
  border-top: 1px solid #e9ecef;
}

.comment-input {
  position: relative;
  width: 100%;
  min-height: 40px;
}

.textarea {
  width: 100%;
  min-height: 40px;
  padding: 10px 10px 10px 16px;
  word-wrap: break-word;
  line-height: 20px;
}

.textarea:empty:not(:focus)::before {
  content: 'Type your comments here';
  position: absolute;
}

.modal-body {
  max-height: 200px;
  overflow-y: scroll;
}

<link href="https://stackpath.bootstrapcdn.com/bootstrap/4.1.3/css/bootstrap.min.css" rel="stylesheet" />
<div class="modal" role="dialog">
  <div class="modal-dialog">
    <div class="modal-content">
      <div class="modal-header"></div>
      <div class="modal-body">
        <p>The standard Lorem Ipsum passage, used since the 1500s "Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris
          nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id
          est laborum." Section 1.10.32 of "de Finibus Bonorum et Malorum", written by Cicero in 45 BC "Sed ut perspiciatis unde omnis iste natus error sit voluptatem accusantium doloremque laudantium, totam rem aperiam, eaque ipsa quae ab illo inventore
          veritatis et quasi architecto beatae vitae dicta sunt explicabo. Nemo enim ipsam voluptatem quia voluptas sit aspernatur aut odit aut fugit, sed quia consequuntur magni dolores eos qui ratione voluptatem sequi nesciunt. Neque porro quisquam
          est, qui dolorem ipsum quia dolor sit amet, consectetur, adipisci velit, sed quia non numquam eius modi tempora incidunt ut labore et dolore magnam aliquam quaerat voluptatem. Ut enim ad minima veniam, quis nostrum exercitationem ullam corporis
          suscipit laboriosam, nisi ut aliquid ex ea commodi consequatur? Quis autem vel eum iure reprehenderit qui in ea voluptate velit esse quam nihil molestiae consequatur, vel illum qui dolorem eum fugiat quo voluptas nulla pariatur?"</p>
      </div>
      <div class="modal-footer">
        <div class="comment-input">
          <div class="textarea" contenteditable="true"></div>
        </div>
      </div>
    </div>
  </div>
</div>

Answer 2

你使用了错误的属性，它应该是min-height而不是max-height，请参考下面的例子！

.modal-footer {
  display: flex;
  align-items: center;
  justify-content: flex-end;
  border-color: #e0e0e7;
  padding: 15px 20px 15px 55px;
  min-height: 70px;
  border-top: 1px solid #e9ecef;
}

.comment-input {
  position: relative;
  width: 100%;
  min-height: 40px;
}

.textarea {
  max-height: 80px !important;
  overflow: auto;
  width: 100%;
  min-height: 40px;
  padding: 10px 10px 10px 16px;
  word-wrap: break-word;
  line-height: 20px;
}

.textarea:empty:not(:focus)::before {
  content: 'Type your comments here';
  position: absolute;
}

<!doctype html>
<html lang="en">

<head>
  <!-- Required meta tags -->
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">

  <!-- Bootstrap CSS -->
  <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/css/bootstrap.min.css" integrity="sha384-Gn5384xqQ1aoWXA+058RXPxPg6fy4IWvTNh0E263XmFcJlSAwiGgFAW/dAiS6JXm" crossorigin="anonymous">

  <title>Hello, world!</title>
</head>

<body>
  <div class="" role="dialog"> <!-- I have removed the modal class so that the modal is visible, please ignore this one change -->
    <div class="modal-dialog">
      <div class="modal-content">
        <div class="modal-header"></div>
        <div class="modal-body"></div>
        <div class="modal-footer">
          <div class="comment-input">
            <div class="textarea" contenteditable="true"></div>
          </div>
        </div>
      </div>
    </div>
  </div>

  <!-- Optional JavaScript -->
  <!-- jQuery first, then Popper.js, then Bootstrap JS -->
  <script src="https://code.jquery.com/jquery-3.2.1.slim.min.js" integrity="sha384-KJ3o2DKtIkvYIK3UENzmM7KCkRr/rE9/Qpg6aAZGJwFDMVNA/GpGFF93hXpG5KkN" crossorigin="anonymous"></script>
  <script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.12.9/umd/popper.min.js" integrity="sha384-ApNbgh9B+Y1QKtv3Rn7W3mgPxhU9K/ScQsAP7hUibX39j7fakFPskvXusvfa0b4Q" crossorigin="anonymous"></script>
  <script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/js/bootstrap.min.js" integrity="sha384-JZR6Spejh4U02d8jOt6vLEHfe/JQGiRRSQQxSfFWpi1MquVdAyjUar5+76PVCmYl" crossorigin="anonymous"></script>
</body>

</html>