GeolocationCoordinates: longitude property
Baseline Widely available
This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015.
Secure context: This feature is available only in secure contexts (HTTPS), in some or all supporting browsers.
The longitude
read-only property of the GeolocationCoordinates
interface is a number which represents the longitude of a geographical position, specified in decimal degrees.
Together with a timestamp, given as Unix time in milliseconds, indicating a time of measurement, the GeolocationCoordinates
object is part of the GeolocationPosition
interface, which is the object type returned by Geolocation API functions that obtain and return a geographical position.
Value
The value in longitude
is the geographical longitude of the location on
Earth described by the Coordinates
object, in decimal degrees. The value is
defined by the World Geodetic System 1984 specification (WGS 84).
Note: The zero meridian (also known as the prime meridian or the reference meridian) is not precisely the same as the Greenwich meridian that most people think of. It is, instead, the IERS Reference Meridian, which is located 5.3 arcseconds (102 meters / 335 feet) east of the Greenwich meridian. This is the same standard used by the Global Positioning System (GPS).
Examples
In this simple example, we fetch the user's location and display the resulting coordinates once they're returned.
JavaScript
The JavaScript code below creates an event listener so that when the user clicks on a button, the location information is retrieved and displayed.
let button = document.getElementById("get-location");
let latText = document.getElementById("latitude");
let longText = document.getElementById("longitude");
button.addEventListener("click", () => {
navigator.geolocation.getCurrentPosition((position) => {
let lat = position.coords.latitude;
let long = position.coords.longitude;
latText.innerText = lat.toFixed(2);
longText.innerText = long.toFixed(2);
});
});
After setting up variables to more conveniently reference the button element and the
two elements into which the latitude and longitude will be drawn, the event listener is
established by calling addEventListener()
on the <button>
element. When the user clicks the button, we'll fetch
and display the location information.
Upon receiving a click
event, we call
getCurrentPosition()
to request the
device's current position. This is an asynchronous request, so we provide a callback
which receives as in put a GeolocationPosition
object describing the
determined position.
From the GeolocationPosition
object, we obtain the user's latitude and
longitude using position.coords.latitude
and
position.coords.longitude
so we can update the displayed coordinates. The
two <span>
elements are updated to display the corresponding values
after being converted to a value with two decimal places.
HTML
The HTML used to present the results looks like this:
<p>
Your location is <span id="latitude">0.00</span>° latitude by
<span id="longitude">0.00</span>° longitude.
</p>
<button id="get-location">Get My Location</button>
Result
Take this example for a test drive here:
Specifications
Specification |
---|
Geolocation # latitude-longitude-and-accuracy-attributes |
Browser compatibility
BCD tables only load in the browser
See also
- Using the Geolocation API
- The
GeolocationCoordinates
interface it belongs to. - The
GeolocationPosition
interface, which is the top-level interface used to return geolocation data from the Geolocation API functionsGeolocation.getCurrentPosition()
andwatchPosition()
.