Learning English vocabulary. Imitates the cards for learning a language. JSON contains 3 arrays with English words, Ukrainian translation and transcription. JavaScript contains only arrays with numbers(indexes from 0 to 999), keys so to say to acces the words from JSON. At the beginning all indexes are at "unknownWordsArr" but during learning process they pass to other arrays(lists); Onload script checks if user already has arrays with indexes saved in local storage, if so the arrays are updated. Every time user changes location of a word its location is updated and saved to local storage.