Do PHP scripts run in parallel when calling another PHP page?

When calling another PHP page from a PHP script, the scripts do not run in parallel by default. Each script will execute sequentially, one after the other. If you want to run PHP scripts in parallel, you can use multi-threading or multi-processing techniques. One common approach is to use the `pcntl_fork()` function to create child processes that can run concurrently.

// Example of running PHP scripts in parallel using pcntl_fork()

$pid = pcntl_fork();

if ($pid == -1) {
    die('Could not fork');
} else if ($pid) {
    // Parent process
    pcntl_wait($status); // Wait for child process to finish
} else {
    // Child process
    // Code to execute in parallel
    exit();
}