如何在Scalajs中使用Ajax上传文件

import org.scalajs.dom
import org.scalajs.dom.raw.{Event, XMLHttpRequest}

object FileUploadExample {
  def main(args: Array[String]): Unit = {
    val formId = "uploadForm"
    val form = dom.document.getElementById(formId).asInstanceOf[dom.raw.HTMLFormElement]

    form.addEventListener("submit", (event: dom.Event) => {
      event.preventDefault()

      val file = form.files.item(0)
      if (file != null) {
        val xhr = new XMLHttpRequest()
        xhr.open("POST", "/upload", true)
        xhr.setRequestHeader("Content-Type", file.`type`)

        xhr.upload.onprogress = (event: dom.ProgressEvent) => {
          val percent = (event.loaded / event.total) * 100
          println(s"Upload progress: $percent%")
        }

        xhr.onload = (event: dom.Event) => {
          if (xhr.status == 200) {
            val response = xhr.responseText
            println(s"Upload complete. Response: $response")
          } else {
            println(s"Upload failed. Status: ${xhr.status}")
          }
        }

        xhr.send(file)
      }
    })
  }
}