PHP: Cookie in browser, but receive index undefined error

问题

I'm setting my cookie properly in my code, for example:

$expire = time()+60*60*24*30;          
setcookie("userid", 27, $expire);

But then when I attempt to access the cookie to use it's value ($userid = $_COOKIE['userid'];), I keep receiving, "undefined index: userid"

If I check my browser's (in this case, Firefox) cookies I can clearly see that my cookie is there and set:

Any and all assistance is appreciated...this is driving me insance. Thanks!

回答1:

I see that cookie has 'path' attribute set to some directory on the server. Path limits the scope. When path is not explicitly specified browser uses script uri. Most likely your script which reads the cookie is at different location then the one which sets cookie. Try setting path to / eg

$expire = time()+60*60*24*30;          
setcookie("userid", 27, $expire,'/');

来源：https://stackoverflow.com/questions/7394256/php-cookie-in-browser-but-receive-index-undefined-error