watchPosition() continuously monitors the user’s position and calls a callback whenever the position changes.

const watchId = navigator.geolocation.watchPosition(
  (position) => {
    console.log('Position updated:', position.coords);
    // Update map, log movement, etc.
  },
  (error) => console.error(error),
  { enableHighAccuracy: true }
);

// Stop watching position updates
navigator.geolocation.clearWatch(watchId);
console.log('Stopped watching position');

• Real-time location tracking (maps, delivery tracking)
• Fitness apps (running routes, distance tracking)
• Geofencing (trigger actions when entering/leaving areas)

• watchPosition() — continuous position updates
• Returns a watch ID for stopping updates
• clearWatch(id) — stop watching
• More battery-intensive than one-time requests

• MDN: Geolocation.watchPosition