Do you know Learning with Texts (LWT), ReadLang, Lingq,... LangBrowser works the same way.

Learn Languages in Context while browsing and reading for Linguist

LangBrowser - Learn a language while browsing and reading. Add context to the vocabulary then practice, and learn in context.

“FOCUS ON CONTEXT WITH TRANSLATION”

- Translate words & phrases live on any web page
- Highlight word to learn without practice