This section describes how PHP supports cookies. setcookie() is the function to set a cookie to the HTTP response. $_COOKIE is the array containing cookies received in the next HTTP request.
PHP supports cookies with following elements:
1. setcookie() - A built-in function that defines a cookie to be sent in the HTTP response as a header line.
Like other header lines, cookies must be sent before any output from your script (this is a protocol restriction).
This requires that you place calls to this function prior to any output, including <html> and <head> tags
as well as any whitespace. If output exists prior to calling this function,
setcookie() will fail and return FALSE.
The syntax of calling setcookie() is:
bool setcookie(string name, string value, int expire)
"name" is the name of this cookie.
"value" is the value of this cookie. "value" is optional. If "value" is not provided, this cookie will be set
in the HTTP response without any value.
"expire" is the time when this cookie should be expired. "expire" is optional. If "expire" is not provided,
this cookie will saved in browser memory only. If "expire" is provided, it represents a time in number of seconds
since the epoch. If the provided time is a future time, this cookie will be saved on the hard disk of the browser system.
For example, setcookie("user", "Herong") will set a cookie named as "user" in the HTTP response.
2. $_COOKIE - A built-in array that stores cookies returned back from the browser in the next HTTP request. Cookie names will be used
as array keys. For example, $_COOKIE["user"] returns the cookie value, "Herong", included in the HTTP request.
