jQuery带动画效果的CSS3表单输入框验证代码

html,
body {
  background-color: #F4F4F4;
  display: flex;
  width: 100%;
  height: 100%;
  align-items: center;
  font-family: "Work Sans", sans-serif;
  justify-content: center;
}

.exp-container {
  width: 100%;
  padding: 30px;
  box-sizing: border-box;
  max-width: 600px;
}

.exp {
  display: flex;
  flex-direction: column-reverse;
  width: 100%;
  margin-bottom: 30px;
  position: relative;
  flex-wrap: wrap;
}

.exp__label {
  transition: 0.3s;
  margin-bottom: 5px;
}

.exp__label:before {
  content: attr(data-icon);
  font-weight: normal;
  font-family: "Ionicons";
  font-size: 24px;
  position: absolute;
  left: 0;
  transform: rotateY(90deg);
  bottom: 0;
  height: 52px;
  background: transparent;
  color: #000;
  transform-origin: left;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: color .3s 0s ease, transform .3s 0s ease;
  width: 42px;
}

.exp__input {
  border: 1px solid #ddd;
  padding: 0 10px;
  width: 100%;
  height: 52px;
  transition: 0.3s;
  font-weight: normal;
  box-sizing: border-box;
  font-family: "Work Sans", sans-serif;
  outline: none;
}

.exp__input:focus {
  padding-left: 42px;
  border-color: #bbb;
}

.exp__input:focus + label:before {
  transform: rotateY(0deg);
}

.exp__input:valid {
  padding-left: 42px;
  border-color: green;
}

.exp__input:valid + label {
  color: green;
}

非常简单的一款带动画效果的CSS3表单输入框验证代码，当输入框聚焦时出现图标动画，还有验证邮箱地址格式是否正确等功能。