// Polyfill for older browsers (if needed)
if (!document.addEventListener) {
  document.attachEvent('onvisibilitychange', handleVisibilityChange);
} else {
  document.addEventListener('visibilitychange', handleVisibilityChange);
}

// Variables
var originalTabTitle = document.title;
var unreadMessageTitle = "(1) Unread Message";

// Event handler for tab visibility changes
function handleVisibilityChange() {
  if (document.hidden) {
      document.title = unreadMessageTitle; // Show unread message when tab is not active
  } else {
      document.title = originalTabTitle; // Restore the original title when tab becomes active
  }
}

// Fallback for browser-specific hidden properties
var hidden = document.hidden !== undefined ? 'hidden' :
           document.msHidden !== undefined ? 'msHidden' :
           document.webkitHidden !== undefined ? 'webkitHidden' : null;

if (hidden) {
  document.addEventListener('visibilitychange', handleVisibilityChange);
}