上移的输入框

<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title></title>
<style>
  .box{
    width:200px;
    height:30px;
    border:1px solid #aaa;
    position: relative;
    border-radius: 5px;
  }
  input{
    height:30px;
    width:100%;
    border-radius: 5px;
  }
  span{
    position:absolute;
    top:10px;
    left:10px;
    background: pink;
    transition: all 0.5s ease-in;
    background: pink;
  }
</style>
</head>
<body>
<div class="box">
  <span>姓名:</span>
  <input type="text">
</div>
</body>
<script src="js/jquery-1.4.2.min.js"></script>
<script>
  $(function(){
    $('input').focus(function(){
      $('span').css('top','-10px');
    });
    $('input').blur(function(){
    if($('input').val()=="){
      
$('span').css('top','10px');
      }
    else{
    
$('span').css('top','-10px');
    }
})
})
//原生

<script>
window.onload = function(){
var oInput = document.querySelector('input');
var oSpan = document.querySelector('span');
oInput.onfocus = function(){
oSpan.style.top = -10 + 'px';
};
oInput.onblur = function(){
if(oInput.value == ""){
console.log('我的内容为空');
oSpan.style.top = 10 + 'px';
}else{
oSpan.style.top = -10 + 'px';
};
};
}
</script>

 
</script>
</html>
原文地址:https://www.cnblogs.com/TTTK/p/6322656.html