Javascriptの処理結果をHTMLに表示させたい

GoogleのSpeechToTextとTranslateを利用して、日本語で音声入力した結果を英語に翻訳するものを作りたいと考えております。
ボタンで音声入力をするのですがその入力画面と処理結果を表示させる画面を分けたいと考えております。
処理結果のみ別HTMLで表示させるにはどうしたらよいのでしょうか。
プログラミングの学習を始めたばかりで、とても初歩的な質問だと思いますがご回答お願いいたします。

main.html
1<!DOCTYPE html>
2<html>
3<head>
4    <meta charset="UTF-8" />
5    <title>サンプル</title>
6</head>
7<body>
8<button onclick="startRecording()">開始</button>
9<button onclick="endRecording()">終了</button>
10<div class="japanese" id="output_ja"></div>
11<div class="english" id="output_en"></div>
12
13<script src="api_key.js"></script>
14<script src="./lib/recorder.js"></script>
15<script src='main.js'></script>
16</body>
17</html>

main.js
1let audio_context;
2let recorder;
3
4function arrayBufferToBase64(buffer) {
5    let binary = '';
6    let bytes = new Float32Array(buffer);
7    let len = bytes.byteLength;
8    for (let i = 0; i < len; i++) {
9        binary += String.fromCharCode(bytes[i]);
10    }
11    return window.btoa(binary);
12}
13
14function startUserMedia(stream) {
15    let input = audio_context.createMediaStreamSource(stream);
16
17    recorder = new Recorder(input);
18}
19
20
21let startRecording = function () {
22    audio_context.resume()
23    recorder && recorder.record();
24    console.log("record start")
25};
26
27let endRecording = function () {
28    recorder && recorder.stop();
29    console.log("record stop");
30
31    // create WAV download link using audio data blob
32    audioRecognize();
33
34    recorder.clear();
35};
36
37function audioRecognize() {
38    recorder && recorder.exportWAV(function (blob) {
39        let reader = new FileReader();
40        reader.onload = function () {
41            let result = new Uint8Array(reader.result); // reader.result is ArrayBuffer
42            let data = {
43                "config": {
44                    "encoding": "LINEAR16",
45                    "sampleRateHertz": 48000,
46                    "languageCode": "ja-JP"
47                },
48                "audio": {
49                    "content": arrayBufferToBase64(result)
50                }
51            };
52            console.log("audio send...");
53            fetch('https://speech.googleapis.com/v1/speech:recognize?key=' + apiKey, {
54                method: 'POST',
55                headers: {
56                    'Content-Type': 'application/json; charset=utf-8'
57                },
58                body: JSON.stringify(data)
59            }).then(function (response) {
60                return response.text();
61            }).then(function (text) {
62                let result_json = JSON.parse(text);
63                text = result_json.results[0].alternatives[0].transcript
64                output_ja.innerHTML += "\n" + text
65                console.log("RESULT: " + text);
66                console.log(result_json.results[0].alternatives[0].transcript);
67                console.log(data)
68            
69            let fromLang = 'ja';
70            let toLang = 'en';
71            let URL = "https://translation.googleapis.com/language/translate/v2?key="+apiKey+"&q="+encodeURI(text)+"&source="+fromLang+"&target="+toLang
72            let xhr = new XMLHttpRequest()
73            xhr.open('POST', [URL], false)
74            xhr.send();
75            if (xhr.status === 200) {
76              let json = xhr.responseText;
77              let obj = JSON.parse(json);
78              result = obj.data.translations[0].translatedText
79              output_en.innerHTML += "\n" + result
80              console.log("RESULT: " + text);
81              console.log(obj.data.translations[0].translatedText);
82            }
83          });
84        };
85        reader.readAsArrayBuffer(blob)
86
87    });
88}
89
90window.onload = function init() {
91    try {
92        // webkit shim
93        window.AudioContext = window.AudioContext || window.webkitAudioContext;
94        navigator.getUserMedia = navigator.getUserMedia || navigator.webkitGetUserMedia;
95        window.URL = window.URL || window.webkitURL;
96
97        audio_context = new AudioContext();
98    } catch (e) {
99        alert('No web audio support in this browser!');
100    }
101
102    navigator.getUserMedia({audio: true}, startUserMedia, function (e) {
103    });
104};