When visiting Khan Academy's homepage https://www.khanacademy.org, everything should function correctly. In cases when YouTube is blocked in China and Iran, we use alternative video players to show the instructional videos. If you are having problems accessing the site, please let us know.
If you're looking for Khan Academy content in Chinese (simplified), visit https://zh-hans.khanacademy.org for a translated version of the site.
You can also find some Khan Academy videos in Farsi/Persian at https://fa.khanacademy.org.