How to get the video id.

1. Youtube

• In the address bar, the word between "?v=" and "&" is the video id.

  

• Or you can click the share.

  

  The word after "be/" is the video id.

  

2. Bilibili

• In the address bar, the word after "video/" is the video id.

  

• Or you can use the Bilibili mobile app.
  The word here is the video id.