如何使用ajax上传图片到服务器目录？

<form id="uploadForm" enctype="multipart/form-data">
  <input type="file" name="image" id="imageInput">
  <input type="button" value="上传" onclick="uploadImage()">
</form>

function uploadImage() {
  var imageFile = document.getElementById("imageInput").files[0];
  var formData = new FormData();
  formData.append("image", imageFile);

  var xhr = new XMLHttpRequest();
  xhr.open("POST", "/upload", true);
  xhr.onload = function() {
    if (xhr.status === 200) {
      console.log("图片上传成功！");
    } else {
      console.error("图片上传失败！");
    }
  };
  xhr.send(formData);
}

const express = require("express");
const multer = require("multer");

const app = express();
const upload = multer({ dest: "uploads/" });

app.post("/upload", upload.single("image"), (req, res) => {
  // 在uploads/目录中保存上传的图片
  // 可以根据需求对上传的图片进行处理或验证

  res.sendStatus(200);
});

app.listen(3000, () => {
  console.log("服务器已启动，监听端口3000");
});