<input id="upload" type="file"/>
 <button id="upload-btn">upload</button>
 document.getElementById('upload-btn').onclick = function(){ 
  var oInput = document.getElementById('upload'); 
  var file = oInput.files[0];  //选取文件
  var formData = new FormData(); //创建表单数据对象
  formData.append('file',file); //将文件添加到表单对象中
  fetch({       //传输
   url:'./',
   mothod:'POST',
   body:formData 
  }) 
  .then((d)=>{
  console.log('result is',d);
  alert("上传完毕！")
  })
 }

 table{
   border-collapse:collapse; /* 为表格设置合并边框模型 */
   margin:50px;
   text-align:center; /* 设置文字居中 */
  } 
  table tr{
   border:none;
  } 
  table.tab td{
   width:50px;
   height:50px;
   border:5px inset blue;
  } 
  table.tab td:hover{
   border:5px solid red;
   cursor: pointer;
  }
  <table class="tab">
  <tr>
   <td>1</td>
   <td>2</td>
   <td>3</td>
  </tr>
  <tr>
   <td>4</td>
   <td>5</td>
   <td>6</td>
  </tr>
  <tr>
   <td>7</td>
   <td>8</td>
   <td>9</td>
  </tr>
  </table>