昨天，在工作中遇到了一个有关Session cookie的问题。以前没有太注意过cookie，只知道它是用来存一些东西的，常常会生成一些垃圾文件，常常要删除。cookie实际上有两种类型Session cookie和persistent cookie。
         Session cookie 又叫 transient cookie，它被存储在临时的存储器中，浏览器关闭后不会保留
         Persistent cookie 又叫 permenent cookie，它被存储在用户的硬件上，直到过期或这是用户自行删除

Yesterday, a question about session cookie in my job. I did not pay attention on cookie, and just knew that cookie is used to store something and always create something as rubbish of OS. After finished the job I learn about the types of the cookie. There are two types of cookie: session cookie and persistent cookie.

Session cookie also called a transient cookie, it is stored in temporary memory and is not retained after the browser is closed.

Persistent cookie also called a permenent cookie, it is stored on user's hard drive until it expires or be deleted by the user.