Skip to content

FAQ

Frequently Asked Questions

I can't scan text in Firefox!

In Firefox's Manifest V3, host permissions are treated as opt-in. For Yomitan to work properly, the recommended permissions must be explicitly set. In the Yomitan welcome page, go to the Recommended Permissions (Important) section and check Enable recommended permissions.

I'm having problems importing dictionaries in Firefox, what do I do?

Yomitan uses the cross-browser IndexedDB system for storing imported dictionary data into your user profile. Although everything "just works" in Chrome, depending on settings, Firefox users can run into problems due to browser bugs. Yomitan catches errors and tries to offer suggestions about how to work around Firefox issues, but in general at least one of the following solutions should work for you:

  • Make sure you have cookies enabled. It appears that disabling them also disables IndexedDB for some reason. You can still have cookies be disabled on other sites; just make sure to add the Yomitan extension to the whitelist of whatever tool you are using to restrict cookies. You can get the extension "URL" by looking at the address bar when you have the search page open.
  • Make sure that you have sufficient disk space available on the drive Firefox uses to store your user profile. Firefox limits the amount of space that can be used by IndexedDB to a small fraction of the disk space actually available on your computer.
  • Make sure that you have history set to "Remember history" enabled in your privacy settings. When this option is set to "Never remember history", IndexedDB access is once again disabled for an inexplicable reason.
  • As a last resort, try using the Refresh Firefox feature to reset your user profile. It appears that the Firefox profile system can corrupt itself preventing IndexedDB from being accessible to Yomitan.

Will you add support for online dictionaries?

Online dictionaries will not be implemented because it is not possible to support them in a robust way. In order to perform deinflection, Yomitan must execute dozens of database queries for every single word. Factoring in network latency and the fragility of web scraping, it would not be possible to maintain a good and consistent user experience.

Is it possible to use Yomitan with files saved locally on my computer with Chrome?

In order to use Yomitan with local files in Chrome, you must first tick the Allow access to file URLs checkbox for Yomitan on the extensions page. Due to the restrictions placed on browser addons in the WebExtensions model, it will likely never be possible to use Yomitan with PDF files.

Is it possible to delete individual dictionaries without purging the database?

Yomitan is able to delete individual dictionaries, but keep in mind that this process can be very slow and can cause the browser to become unresponsive. The time it takes to delete a single dictionary can sometimes be roughly the same as the time it originally took to import, which can be significant for certain large dictionaries.

Why aren't EPWING dictionaries bundled with Yomitan?

The vast majority of EPWING dictionaries are proprietary, so they are unfortunately not able to be included in this extension due to copyright reasons.