PHP Predefined Variables Example

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Predefined variables in PHP are variables that are automatically accessible for usage without the need to declare or initialize them. These variables include information about the server, user, and environment in which the script is operating.

Two commonly used predefined variables are:

• $_SERVER: This variable contains an array of server-related information, such as the server name, host, and user agent.
• $_SERVER['SERVER_NAME']: This specific element of the $_SERVER array holds the name of the server where the script is executed.
• $_SERVER['HTTP_USER_AGENT']: This element contains the user agent string of the client's web browser.

For example, you can access the server name using $_SERVER['SERVER_NAME'] and the user agent string using $_SERVER['HTTP_USER_AGENT'].