我正在使用簡單的開始和停止按鈕在網(wǎng)頁上錄制音頻。該文件存儲為 blob。我希望這個 blob 作為文件在對我的后端 API 的 POST 調(diào)用的正文中轉(zhuǎn)換為 base64。我嘗試了以下代碼：'use strict'var log = console.log.bind(console),  id = val => document.getElementById(val),  ul = id('ul'),  gUMbtn = id('gUMbtn'),  start = id('start'),  stop = id('stop'),  stream,  recorder,  counter = 1,  chunks,  media;var mv = id('mediaVideo'),  mediaOptions = {    video: {      tag: 'video',      type: 'video/webm',      ext: '.mp4',      gUM: { video: true, audio: true }    },    audio: {      tag: 'audio',      type: 'audio/ogg',      ext: '.ogg',      gUM: { audio: true }    }  }media = mediaOptions.audio;navigator.mediaDevices.getUserMedia(media.gUM).then(_stream => {  stream = _stream;  id('btns').style.display = 'inherit';  start.removeAttribute('disabled');  recorder = new MediaRecorder(stream);  recorder.ondataavailable = e => {    chunks.push(e.data);    let blob = new Blob(chunks, { type: media.type })      , url = URL.createObjectURL(blob)      , li = document.createElement('li')      , mt = document.createElement(media.tag)      , hf = document.createElement('a');    if (recorder.state == 'inactive') makeLink(url, li, mt, hf);    log('data receiving');    var reader = new FileReader();    reader.readAsDataURL(blob);    console.log(reader);    var xhttp = new XMLHttpRequest();    xhttp.open("POST", "http://localhost:8080/rest/api/v1/audio/submit", (JSON.stringify(reader)), true);    xhttp.setRequestHeader('Content-Type', 'application/json');    xhttp.send(JSON.stringify(reader));  };}).catch(log);start.onclick = e => {  start.disabled = true;  stop.removeAttribute('disabled');  chunks = [];  recorder.start();}stop.onclick = e => {  stop.disabled = true;  recorder.stop();  start.removeAttribute('disabled');}不幸的是，我無法弄清楚如何在 JavaScript 錄制后發(fā)布。