Reference: Wesbos/JavaScript30/ soyaine/JavaScript30 (Chinese detailed notes) amelieyeh/JS30 (English) winar-jin (Chinese)/JavaScript30-Challenge dwatow/JavaScript30 (Chinese) dustinhsiao21/Javascript30-dustin (Chinese) Thorsten Frommen (English blog, including his code refinement) guahsu/JavaScript30 (Chinese) JavaScript30-liyuechun (Chinese)