To redirect users to new location, just drop this header() line in your PHP file. Remember that header() function must be called before any actual output is sent, otherwise you might run into error.
If you are using PHP just drop the following line on top of your script, this will detect whether the request was made using Ajax or not.
Cookies are small files created by server on a user computer, cookies are primarily used to store little information about anything, and when user visits your website next time the information stored in cookies can be retrieved and used in various purpose.
If you need to check whether curl is available in a web server, you can use snippet below to check available curl. The code below will check if curl is available and enabled in the web server.Usage :