questions about cookie

[remote2]

1. what is the default expire time for a cookie if i dont set the expire parameter?

2. If i set a cookie to expire in 20min and 5min later i refresh the page will the cookie expire in 15min or in another 20min?

3. Is it possible to use cookie like a session? where the cookie expire when the user close the browser?

[RGBlackmore]

1. what is the default expire time for a cookie if i dont set the expire parameter?

when you close the browser

2. If i set a cookie to expire in 20min and 5min later i refresh the page will the cookie expire in 15min or in another 20min?

when you send a cookie, it's stored in the local client machine. The data for the expire time is like "day month year min:secs". If you refresh, the cookie don't 'refresh' the expire time; this die in 15 min. If you want to refresh the cookie, you must kill the old cookie and set a new one.

3. Is it possible to use cookie like a session? where the cookie expire when the user close the browser?

in fact, when you use session_start(); and then session_id();, if the browser likes, it can store a cookie named PHPSESSID, telling the expire time that is when the client close the browser. YOU can use cookies for sessions; YOU control the expire time. If you dont set it, it assume the cookie dies when the client close the browser.

PS: sorry for my poor english 😛

[remote2]

hmm..~
i've done a little experiment...

if(empty($_COOKIE['session_id'])){
  $this->session_id = md5(uniqid($_SERVER['REMOTE_ADDR']));
  setcookie('session_id', $this->session_id, time()+60);
  $this->is_new = true;
}
else{
  $this->session_id = $_COOKIE['session_id'];
}
echo "session_id=$this->session_id"._BR;
echo '_COOKIE[\'session_id\'] ='. $_COOKIE['session_id']._BR;

1. it seems that... the cookie doesn't expire when i close the browser...

2. RGBlackmore is right.. the cookie doesn't refresh.

3. cookie still active when i close and reopen the browser...

and a new question.

4. how do you clear a cookie?? like when a user logs out... do i use unset() or something?

[RGBlackmore]

from php.net (http://www.php.net/manual/en/function.setcookie.php):

" All the arguments except the name argument are optional. If only the name argument is present, the cookie by that name will be deleted from the remote client. "

it you have a cookie named $cookietest, just do

setcookie("cookietest"); and it dies