index.html

<!DOCTYPE html>
<html>
	<body>
		<p>Click in the button to get your coordinates (long/lat).</p>
		<button onclick="getLocation()">Find my Location</button>
		<p id="demo"></p>
		<script>
		var x = document.getElementById("demo");

		function getLocation() {
		  if (navigator.geolocation) {
		    navigator.geolocation.getCurrentPosition(showPosition);
		  } else { 
		    x.innerHTML = "Geolocation is not supported by this browser, try Mozila Firefox, Chrome, Brave, etc.";
		  }
		}

		function showPosition(position) {
		  x.innerHTML = "Latitude: " + position.coords.latitude + 
		  "<br>Longitude: " + position.coords.longitude;
		}
		</script>
	</body>
</html>


<!-- Fontes
https://developer.mozilla.org/pt-BR/docs/Web/API/Geolocation/getCurrentPosition -

https://developer.mozilla.org/pt-BR/docs/Web/API/Geolocation_API 

https://www.w3schools.com/html/tryit.asp?filename=tryhtml5_geolocation -->