How do you get the user's current position with the Geolocation API?

Call navigator.geolocation.getCurrentPosition(successCallback), which asynchronously invokes your function with a position object once the user grants permission.

function getLocation() {
    navigator.geolocation.getCurrentPosition(showPosition);
}

function showPosition(position) {
    console.log("Latitude: " + position.coords.latitude);
    console.log("Longitude: " + position.coords.longitude);
}

getLocation();

Key points:

• Asynchronous - doesn't return immediately, calls callback when ready
• Requires permission - browser prompts user
• HTTPS required - won't work on insecure origins (except localhost)

The position object contains:

• coords.latitude - Latitude in degrees
• coords.longitude - Longitude in degrees
• coords.accuracy - Accuracy in meters
• coords.altitude - Altitude (if available)

Go deeper:

• MDN — getCurrentPosition() — full signature including the optional third options argument (enableHighAccuracy, timeout, maximumAge).