How can different web servers and platforms affect the execution of startup scripts in PHP?

Different web servers and platforms can affect the execution of startup scripts in PHP due to variations in configuration settings, server capabilities, and PHP versions. To ensure consistent execution of startup scripts across different environments, it is recommended to use a standardized approach such as utilizing the `php.ini` file to set configuration options or using server-independent methods for executing startup scripts.

// Example of setting configuration options in php.ini file
// Add the following line to php.ini file
// auto_prepend_file = /path/to/startup_script.php