How PHP reads COOKIES

View browser Cookies
Let's take a look at the content saved in the browser. If you are using IE5, there is a cookie directory under the windows directory, which contains many text files. The file names are similar to wudong@15seconds%1%.txt, this is the cookie used by the browser to save the value. In earlier versions of IE, the content of cookies can be viewed, but now the content has been encoded. Before the browser obtains a Web page, it first looks at the domain name of the page and determines whether it exists in the cookie. If there is a matched cookie, the browser first delivers the matching cookie to the server, then accept the page sent by the processing server.
Here is an example of a cookie application: when I connect to Amazon.com, the browser sends the previously set cookies to Amazon before accepting the first page. Then, Amazon.com checks the transmitted content to see if there is any relevant information in the database. After matching, a custom page is created for me and sent to it.
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Assign values to cookies
Cookies must be assigned a value before the server sends any content to the client browser. To do this, the cookie settings must be placed in the <HEAD> label:
<? Php
Setcookie ("CookieID", $ USERID );
?>
<HTML>
<BODY>
</BODY>
</HTML>
The setcookie function has six parameters separated by commas:
Cookie name, which is a string such as "CookieID ". Colon, comma, and space are not allowed. This parameter is required, and all other parameters are optional. If only this parameter is provided, the cookie will be deleted.
Cookie value, usually a string variable, for example, $ USERID. You can also assign a question mark (?) to it ?? To skip the value setting.
The time when the cookie expires. If it is omitted (or assigned to zero value), the cookie will expire after the session ends. This parameter can be an absolute time, represented by DD-Mon-yy hh: MM: SS, for example, "24-Nov-99 08:26:00 ". It is more commonly used to set a relative time. This is implemented through the time () function or the mktime function. For example, time () + 3600 will invalidate the cookie after one hour.
A path used to match the cookie. When multiple cookie settings with the same name exist on a server, this parameter is required to avoid confusion. The effect of using the "/" path is the same as that of omitting this parameter. Note that the cookie definition of Netscape places the domain name in front of the path, while PHP is opposite.
The server domain name is also used to match the cookie. Note that a point (.) must be placed before the domain name of the server (.). For example, ".friendshipcenter.com ". Because the parameter is unacceptable unless more than two vertices exist.