What are the potential challenges of implementing a global countdown timer in PHP for an online game?

One potential challenge of implementing a global countdown timer in PHP for an online game is ensuring synchronization across all clients to prevent discrepancies in the countdown. One way to solve this is by utilizing server-side time to calculate the countdown and regularly updating clients with the current countdown value.

// Server-side code to calculate and update countdown timer
$startTime = time(); // Get the current server time as the start time
$endTime = $startTime + 60; // Set the end time for the countdown (e.g., 60 seconds)

// Calculate the remaining time for the countdown
$remainingTime = $endTime - time();

// Update clients with the remaining time
echo json_encode(['remainingTime' => $remainingTime]);