Cookie note _ javascript skills

Cookies are often used, that is, key information is recorded. If you confirm that the information is not retained, you can set it to expire. 1. When Session. Clear () is found during the development process, the Session can be directly identified. Can the Cookie be used?
Cookie. Clear () tried one. If no result exists, the cookie still exists. The answer is no.

Session exists on the server and can be controlled by common programs. However, the Cookie is stored on an independent computer and cannot be directly removed (physically deleted ). However, you can delete the cookie in the browser. When the browser detects that the cookie expiration time is out of the range, the cookie information will not be loaded. Indicates that the cookie information is deleted.

2. In actual development, it is easy to remember the password, that is, to set a longer expiration time. No matter what the user does, watch this small problem for a long time.

However, after a time is set, can the program read the expiration time?

I tried it. {0001-1-1 0:00:00} is the content returned by the cookie expiration time. On January 1, January 1, the total time is 0. I found some information on the Internet,

When the browser sends Cookie information to the server, the validity period is not included.

When the browser sends Cookie information to the server, the validity period is not included. (The Cookie's Expires attribute always returns a datetime value of 0 .)


Now I understand the reason.