This extension can be used to generate Furigana for any Japanese site. You can also modify the level to match your Japanese speaking level. The result is always going to be above your level, so you can decide which Furigana to show!

Apart from that, you can also download other features like:

• Generate your own shared vocabulary lists from your readings.
• Create a known word list that will always be Furigana ignored.
• Track your known words/Kanji across sites, and make weekly goals.
• Change reading difficulty level on the fly with the toggle in the plug-in.
• Learn Japanese (vocabulary and Kanji) by reading what you like.
• Practice hard words or Kanji with flashcards.
• Generate Furigana by entering word.