在Instagram頁面加入下載按鈕與開啟按鈕，透過這些按鈕可以下載或開啟大頭貼與貼文、限時動態、Highlight中的照片或影片
managed to solve it, if it's useful for someone
in line 11 and 123 you need to change getElementsByClassName
right arrow: getElementsByClassName('_9zm2');
left arrow: getElementsByClassName('_9zm0');
Hey, Shortcut Keys don't work. Can it be fixed? Thanks