Which of the following is not a valid property?

The property "coords.timestamp" is not valid in the context of the Geolocation API used in JavaScript. In the Geolocation API, the "coords" object typically contains properties such as latitude, longitude, and altitude, which provide the geographical details of the device's location.

The latitude property represents the north-south position on the Earth's surface, the longitude property represents the east-west position, and the altitude property signifies the height above or below sea level. However, the standard Geolocation API representation does not include a timestamp property directly within the "coords" object. This is likely leading to the confusion regarding its validity.

Understanding the structure of the Geolocation API and the properties that are officially documented will clarify why "coords.timestamp" does not belong to the expected set of properties for that object.