Netflix is a wonderful language-learning tool right up until you have to choose one subtitle track.
Use only your target language and one missed line can send you to another tab. Use only your native language and it becomes harder to connect the words you hear with the translation on screen. Switching tracks every few minutes quickly feels more like operating a settings panel than watching a show.
This guide gives you a more comfortable option: keep Netflix’s selected subtitle at the bottom and add a second language above it. The complete code is included below. Copy it into a MacSide AI HTML memo, register it once, and the memo becomes your own Netflix dual-subtitle controller.
What it looks like
If you select Japanese in Netflix and English in the MacSide memo, English appears above and Japanese stays below. You can reverse the languages, move the extra subtitle closer to the bottom, or change the size while the video is playing.
The snippet also adds:
- Automatic discovery of subtitle tracks available for the current title
- Selection between standard subtitles and closed captions when available
- Adjustable position and font size
- An English-to-Japanese hover dictionary
- Optional pause while hovering over a word
- Keyboard navigation between subtitle cues and configurable short skips
- Full-screen support
It uses subtitle tracks supplied by Netflix for the title you are watching. It does not invent or machine-translate a language that Netflix does not provide.
What you need
The Mac app that hosts the memo and browser connection. It requires Apple silicon and macOS 15.2 or later.
A Chrome extension that runs code from your MacSide memo on sites you explicitly allow.
Copy the complete file with one button. You do not need to edit the code first.
Step 1: install MacSide AI and Browser Connector
Download MacSide AI and open it. Then install MacSide – Browser Connector from the Chrome Web Store.
Open chrome://extensions, select Details for Browser Connector, and turn on Allow User Scripts. Do not grant Netflix access yet. Registering the code first lets Browser Connector discover the site used by the script and display the correct permission request.
Step 2: paste the code into an HTML memo
Open a MacSide AI memo and create an HTML block from the / menu. Use the “Copy code” button below, then paste everything into that single block. The HTML, CSS, and JavaScript belong together; there is no build step.
The block will turn into a dark control panel titled “Netflix 追加字幕.” This is the settings screen for your personal userscript.
Step 3: register the userscript
Click 登録／更新 (Register/update). MacSide AI asks for confirmation before code from a memo can alter Netflix. Registration and enabling require a recent, deliberate click, and MacSide asks again whenever the code changes.
After registration, the Netflix match pattern is synced to Browser Connector.
Step 4: allow the script on Netflix
Click the MacSide – Browser Connector icon in Chrome and open Setup. Under the per-site permissions section, https://www.netflix.com/* now appears as a pending site. Click the button to allow the selected site.
This Netflix entry only appears after the code has been registered. Once permission is granted, reload any Netflix tab that was already open.
Step 5: choose both subtitle languages
Start a title in Netflix and use its normal Audio & Subtitles menu to choose the subtitle you want on the bottom. Return to the MacSide memo; the language menu will populate with tracks detected for the title that is currently playing. Choose the second language there.
You can then adjust:
- Position: top of the video or directly above the lower subtitle
- Font size: 16–48px
- Hover dictionary: show Japanese meanings for words in English subtitles
- Pause on hover: pause only while you inspect a word
- Keyboard controls: jump between subtitle cues or skip a few seconds
For a comfortable first setup, try Japanese at the bottom, English at the top, 39px text, the dictionary on, and pause-on-hover off.
Keyboard controls
| Key | Action |
|---|---|
n | Return to the start of the current cue; repeated presses go to earlier cues |
h | Jump to the next subtitle cue |
b | Skip backward by your chosen number of seconds |
g | Skip forward by your chosen number of seconds |
The hover dictionary downloads about 5MB of public-domain EJDict-hand data the first time it is enabled. It is then stored in the browser’s Netflix origin storage for local reuse.
Copy the complete code
The button below copies the complete memoHTML snippet.
Loading code…
Troubleshooting
The memo stays disconnected or unregistered
Make sure MacSide AI is running and Browser Connector is installed. Browser-side scripts automatically stop when MacSide AI quits.
“Allow User Scripts” is off or missing
Open the extension’s detail page from chrome://extensions and enable the switch. If it is missing, update Chrome and reopen the page.
The script works elsewhere but not on Netflix
After registering the code, open Browser Connector’s Setup page and confirm that https://www.netflix.com/* has been allowed under per-site permissions. Then reload the Netflix tab.
A language is not listed
Available tracks vary by title, season, episode, and region. The snippet can only select tracks Netflix makes available for the title currently playing.
Subtitles drift after the next episode begins
The code matches the subtitle manifest to the current Netflix URL and playback ID so a prefetched next episode is not selected too early. If Netflix changes page state and the cues still drift, reload the tab and click Register/update again.
A memo that behaves like your own extension
Most browser extensions give you a feature exactly as their developer designed it. Browser Connector takes a different approach: code in your memo becomes the feature.
If you want yellow top subtitles, a lower position, or a different shortcut, you can ask an AI to change the memo and register the updated version. The tradeoff is that Netflix can change its interface or internal behavior, so the snippet may occasionally need an update. This is not an official Netflix feature, and MacSide AI is not affiliated with Netflix.
Dual subtitles work best when they remove decisions rather than add more studying. Listen first, glance at the target-language line, hover only when one word blocks the sentence, and use the translation below when you really need it. Then get back to the story.
Download MacSide AI to try the complete setup, then make the memo fit the way you actually watch.