将占位符移动到焦点上的输入上方

Question

我正在寻找css代码,将占位符文本移动到焦点上的输入上方.我在这里找到了这段代码.这段代码是完美的,但我的输入标签被包装在里面<span>,因此一般的兄弟选择器不起作用.有任何想法如何编辑这个CSS？

<div>
  <span class='blocking-span'>
  <input type="text" class="inputText" />
  </span>
  <span class="floating-label">Your email address</span>
</div>

Answer 1

:placeholder-shown在这种情况下,您可以使用CSS伪选择器来检测何时移动假占位符.见下面的例子:

label {
  margin:20px 0;
  position:relative;
  display:inline-block;
}
  
span {
  padding:10px;
  pointer-events: none;
  position:absolute;
  left:0;
  top:0;
  transition: 0.2s;
  transition-timing-function: ease;
  transition-timing-function: cubic-bezier(0.25, 0.1, 0.25, 1);
  opacity:0.5;
}

input {
  padding:10px;
}

input:focus + span, input:not(:placeholder-shown) + span {
  opacity:1;
  transform: scale(0.75) translateY(-100%) translateX(-30px);
}

/* For IE Browsers*/
input:focus + span, input:not(:-ms-input-placeholder) + span {
  opacity:1;
  transform: scale(0.75) translateY(-100%) translateX(-30px);
}

<label>
  <input placeholder=" ">
  <span>Placeholder Text</span>
</label>

Answer 2

使用给定的链接CSS等,只需移动floating-label内部blocking-span.

通过使用position: relative在div该floating-label仍将重新定位就好像它是外blocking-span

div {
  position: relative; /*  make label relate to div  */
  padding-top: 10px;  /*  make space for label      */
}
.inputText {
  font-size: 14px;
  width: 200px;
  height: 25px;
}
.floating-label {
  position: absolute;
  pointer-events: none;
  left: 15px;
  top: 18px;
  transition: 0.2s ease all;
}
input:focus ~ .floating-label,
input:not(:focus):valid ~ .floating-label {
  top: -6px;
}

<div>
  <span class='blocking-span'>
    <input type="text" class="inputText" required/>
    <span class="floating-label">Your email address</span>
  </span>
</div>