How to Delete Cookies in PHP

Deleting an existing cookie from a client machine requires resetting the expiration date. You can in effect set the cookie to nothing and then remove it from the client machine. The best way to do this is to set the expiration date to be some time in the past.

Things You'll Need

• Access to web server where the PHP code will be stored

Instructions

1. Use the mktime() command to create a date in the past and set it to a variable. In this example, January 1, 1970 will be used to better circumvent a problematic discrepancy between the actual date and the date of the client machine.

   $pastdate = mktime(0,0,0,1,1,1970);

2. Use the setcookie() command to reset the cookie. The first parameter is the name of the cookie that is previously determined, the second command is the value (here an empty string), and the third parameter is the expiration date (here the previously set $pastdate variable).

   setcookie("CookieName","",$pastdate);

3. Finish your script and clean up.

Tips & Warnings

• There is a possibility that the client machine's system date and time may be set incorrectly and in such a way that the expiration date may not be earlier than the web server's system date. In this case, the cookie will merely be set to an empty string rather than deleted.

References

• Official PHP Website

Resources

• Read this Article in Spanish