ajax传文件用express的multer接住

1  //input type设为file
2     <input type="file" name="file" id="fileInputElement" />
3     <button id="submit">提交</button>

 1   var btn = document.getElementById(‘submit‘);
 2         var fileInputElement = document.getElementById(‘fileInputElement‘);
 3      
 4         btn.onclick = function () {
 5            
 6             var oMyForm = new FormData();
 7            //append来添加文件,
 8             oMyForm.append("afile", fileInputElement.files[0]);
 9 
10 
11             var oReq = new XMLHttpRequest();
12 
13             oReq.open("POST", "/test");
14           
15          //用FormData生成的对象的好处是,send不需要setRequestHeader
16             oReq.send(oMyForm);
17         }

const app = express();
const multer = require(‘multer‘);
var upload = multer({dest:‘file/‘})//multer的参数dest表示文件接受后存放的地址

app.post(‘/test‘,upload.single(‘afile‘),(req,res)=>{
  
})