javascript - Zhihu search box still has focus even when there is a drop-down menu. Why?

Question

When using the up and down keys to scroll the drop-down menu, the input focus is still retained in the search box. How to do this?

Answer 1

Because the focus should always be on the search box, listening for input keyboard events,
when the direction key is pressed, it is handed over to the drop-down menu management. The drop-down menu calculates the index according to the direction, and adds the activation style to the corresponding entry