Bootstrap 5浮动标签在滚动时与输入框重叠

Question

查看文档中关于textarea浮动标签的https://getbootstrap.com/docs/5.0/forms/floating-labels/，如果内容可滚动，则标签会与输入重叠。

有没有办法防止这种情况并使标签下面的区域可滚动？

- Pattay

Answer 1

这是Bootstrap 5的已知问题：#32800。我所做的是一个小技巧，直到他们修复这个 bug。基本上，我在文本框和标签之间插入了一个伪元素，并设置为白色背景颜色。

.form-floating {
  position: relative;
  max-width: 300px; /* not relevant */
  margin: 40px 20px; /* not relevant */
}

.form-floating:before {
  content: '';
  position: absolute;
  top: 1px; /* border-width (default by BS) */
  left: 1px; /* border-width (default by BS) */
  width: calc(100% - 14px); /* to show scrollbar */
  height: 32px;
  border-radius: 4px; /* (default by BS) */
  background-color: #ffffff;
}

.form-floating textarea.form-control {
  padding-top: 32px; /* height of pseudo element */
  min-height: 80px; /* not relevant */
}

<link href="https://cdn.jsdelivr.net/npm/bootstrap@5.0.0-beta3/dist/css/bootstrap.min.css" rel="stylesheet" integrity="sha384-eOJMYsd53ii+scO/bJGFsiCZc+5NDVN2yr8+0RDqr0Ql0h+rP48ckxlpbzKgwra6" crossorigin="anonymous">

<div class="form-floating fix-floating-label">
    <textarea class="form-control" placeholder="Leave a comment here" id="floatingTextarea"></textarea>
  <label for="floatingTextarea">Comments</label>
</div>

- Black Sheep

Answer 2

首先，将类input_textarea添加到包含textarea输入的父级div中，然后添加以下CSS：

.form-floating.input_textarea label {
    min-width: 90%;
}

    .form-floating.input_textarea label::before {
        content: "";
        position: absolute;
        top: 0.9em;
        z-index: -1;
        width: 100%;
        height: 1.2em;
        background-color: white;
        box-shadow: 0 0 8px 4px #ffffff;
    }


.form-floating.input_textarea > .form-control:focus ~ label, .form-floating.input_textarea > .form-control:not(:placeholder-shown) ~ label, .form-floating.input_textarea > .form-select ~ label {
    opacity: 0.95;
    color: gray;
}

- MohsenB

Answer 3

这里是BlackSheep的答案，稍微适应了SCSS与Bootstrap变量进行样式和尺寸设置，并添加了一个特定类来仅针对文本区域进行目标选择。

$textarea-floating-label-pseudo-element-height: (
    $form-floating-input-padding-t + ($font-size-base * $line-height-base)
  ) * 0.85 - $form-floating-padding-y;
// look at $form-floating-label-transform for "0.85"

.form-floating-textarea {
  position: relative;

  &:before {
    content: "";
    position: absolute;
    top: $input-border-width;
    left: $input-border-width;
    width: calc(100% - $spacer); /* to show scrollbar */
    height: $textarea-floating-label-pseudo-element-height;
    border-radius: $input-border-radius;
    background-color: $input-bg;
  }

  &.form-control:focus,
  &.form-control:not(:placeholder-shown) {
    padding-top: $textarea-floating-label-pseudo-element-height + ($form-floating-padding-y * 0.5); /* leave a little more space below the label */
  }
}

这将看起来像这样：

- maftieu