What is the content storage mechanism in the answer box?

Zhihu will trigger an event to send a request to the server to save the current input content if the focus is lost in the answer box. The machine and the browser can get the information here, but it won't work if the cache is deleted. _ xsrf: the cookie used to get data. _ What is the session recorded by xsrf?

Zhihu answers a question every time the answer box loses focus, an event is triggered to send a request to the server to save the current input content.
Both the machine and the browser can be obtained here.
But it won't work if you delete the cache.
Is it because data is obtained through the cookie _ xsrf?
_ What is session recorded by xsrf?

Reply content:

Zhihu answers a question every time the answer box loses focus, an event is triggered to send a request to the server to save the current input content.
Both the machine and the browser can be obtained here.
But it won't work if you delete the cache.
Is it because data is obtained through the cookie _ xsrf?
_ What is session recorded by xsrf?

Session_id is the premise. The session ID of the browser