How to solve the problem that the value obtained by $_cookie in PHP is different from the stored value

When using "$_COOKIE" to obtain the cookie value, it is different from the expected value. The solutions are: 1. Check whether the name of the cookie is correct and whether the parameters such as domain name, path and expiration time are in line with expectations; 2. Make sure that in the settings Do not repeat the URL encoding or decoding operation when obtaining the cookie value; 3. Clear the browser’s cache, reload the page, and ensure that the cookie parameters set are correct.

The operating system of this tutorial: Windows 10 system, php8.1.3 version, Dell G3 computer.

When using $_COOKIE to obtain the Cookie value is different from the expected value, it may be due to the following reasons:

1. Cookie is not set or the correct parameters are not passed: Make sure that the correct parameters are passed when setting the Cookie. In particular, check whether the name of the Cookie is correct and the parameters such as domain name, path and expiration time. Is it as expected?

2. Cookie value is URL encoded: When setting a Cookie, PHP will URL encode the Cookie value. When reading the Cookie value, PHP will automatically Decoding. If you manually encode the cookie value (such as using the urlencode() function), or perform URL decoding when displaying the cookie value on the page (such as using the urldecode() function), it may result in different readings. to the expected value. Make sure not to repeat URL encoding or decoding operations when setting and getting cookie values.

3. Browser cache issues: Sometimes browsers may cache expired cookies. In order to solve this problem, you can try to clear your browser's cache, reload the page, and ensure that the cookie parameters are set correctly.

If you still cannot solve the problem, you can try the following methods:

• Use the print_r($_COOKIE) function to view all currently available cookies and their values ​​to confirm whether the saved cookies exist and have the correct values.

• Check if the access is immediately after the cookie is set. After the cookie is set, it may take some time to take effect on the next request.

• Check if the cookie is set on the same domain and access under a path. Cookies are associated with domain names and paths. If you access under a different domain name or path, you will not be able to obtain the set Cookie.

• If HTTPS is used To connect, please ensure that the security flag is used when setting and reading cookies, and that the domain name and path match correctly.

• Avoid special characters such as commas, semicolons, etc. in the cookie value. These characters may interfere with parsing of cookie values.

If the problem persists, I recommend checking the parts of the code that set and read cookies to see if there is any other code or logic that is causing the cookie value to change. If the problem persists, further debugging and troubleshooting may be required.

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