I use 10ten (previously Rikuchamp) for Japanese. I don’t think it does full translation, but it gives thorough dictionary lookups (from WWWJDIC) as mouseover tooltips. Very useful if you’re trying to learn the language, but maybe not so much if you just want to read stuff quickly. I think it’s now available for every major browser, but I mostly use it on FF.
Pretty sure Firefox have that too
*For a limited set of languages. Until they add Japanese I won’t be getting much use from it, sadly.
I use 10ten (previously Rikuchamp) for Japanese. I don’t think it does full translation, but it gives thorough dictionary lookups (from WWWJDIC) as mouseover tooltips. Very useful if you’re trying to learn the language, but maybe not so much if you just want to read stuff quickly. I think it’s now available for every major browser, but I mostly use it on FF.