HTTP is a stateless protocol
Stateless means that the server does not know that you have logged in successfully after the first request is sent and the second request is not related to the first request. This feature of Http creates a problem, resulting in a loss of login state. Therefore, the user’s account and password are verified each time the request is made. However, repeated authentication operations will consume computer resources and worsen the user experience. You can go to amusement park, imagine when he enters the gate need to check-in, play a roller coaster need to check-in, see the giant panda also need to recount, playground is also found that every time a recount experience, then validation issue bracelet to visitors to solve the problem, also, the computer can also use this system to solve the problem, we call this bracelet token.
