youtube

https://zh.savefrom.net/1-how-to-download-youtube-video.html

https://www.youtube.com/watch?v=PRc9uV7XWu4&list=PLmVN5jm1ubPV2lFG8OJ8tRE0rU3wevt08&index=20

https://www.yuanzige.com/

https://developers.google.com/chart/

https://chartjs.bootcss.com

https://www.bootcss.com/

https://keet.in/user/lession-video/14