Perfect solution for the issue of Japanese fonts being displayed as SimSun in Firefox

This is an age-old problem. In Firefox, if there are texts with a mix of Chinese and Japanese characters on a webpage, and the web designer hasn't specified anything in the CSS, Japanese text will usually default to SimSun (Songti), which looks very ugly and makes reading Japanese text extremely difficult (in GReader, it simply kills the desire to read). On the other hand, under IE, texts with mixed Chinese and Japanese characters generally display quite perfectly: Chinese in SimSun (Songti) and Japanese in MS Gothic, without the issue of Japanese text being forcibly displayed as SimSun.