模仿 京东快递单号查询功能 

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

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <style>
        * {
            margin: 0;
            padding: 0;
        }
        
        .search {
            position: relative;
            width: 178px;
            margin: 100px;
        }
        
        .con {
            display: none;
            position: absolute;
            top: -40px;
            width: 171px;
            border: 1px solid rgba(0, 0, 0, .2);
            box-shadow: 0 2px 4px rgba(0, 0, 0, .2);
            padding: 5px 0;
            font-size: 18px;
            line-height: 20px;
            color: #333;
        }
        
        .con::before {
            content: '';
            width: 0;
            height: 0;
            position: absolute;
            top: 28px;
            left: 18px;

            /*倒三角型的定义*/
            border: 8px solid #000;
            border-style: solid dashed dashed;
            border-color: #fff transparent transparent;
        } 
    </style>
</head>
<body>
     <div class="search">
        <div class="con">123</div>
        <input type="text" class="jd" placeholder="请输入快递单号"> 
     </div>
     <script>
         //获取元素
         var con = document.querySelector('.con');
         var jd_input = document.querySelector('.jd');
  
         jd_input.addEventListener('keyup',function(){
        /*注意：事件触发keydown和keypress在文本框里面的特点：
        他们两个事件触发的时候，文字还没有落入文本中去*/
             if (this.value == ''){
                con.style.display = 'none';
                
             } else {       
                con.style.display = 'block';
                con.innerHTML = this.value;
            }
             
         })

         //得到焦点
         jd_input.addEventListener('blur',function(){
             con.style.display = 'none';
         })
         //失去焦点
         jd_input.addEventListener('foucs',function(){
             if(jd_input !== ''){
                 con.style.display = 'block'
             }
         })
     </script>
</body>
</html>

 

posted @ 2021-11-22 14:43  嘉琦  阅读(57)  评论(0)    收藏  举报