if (navigator.geolocation) {
  navigator.geolocation.getCurrentPosition(function(position) {
    console.log("Latitude:", position.coords.latitude);
    console.log("Longitude:", position.coords.longitude);
  });
} else {
  alert("Geolocation not supported.");
}

// Lưu dữ liệu vào localStorage
localStorage.setItem("username", "alice");

// Lấy dữ liệu từ localStorage
const name = localStorage.getItem("username");

<div id="target" ondrop="dropHandler(event)" ondragover="dragOverHandler(event)"></div>
<img id="dragme" src="logo.png" draggable="true" ondragstart="dragStartHandler(event)">

function dragStartHandler(e) {
  e.dataTransfer.setData("text", e.target.id);
}
function dropHandler(e) {
  e.preventDefault();
  const id = e.dataTransfer.getData("text");
  e.target.appendChild(document.getElementById(id));
}
function dragOverHandler(e) {
  e.preventDefault();
}

// main.js
const worker = new Worker("worker.js");
worker.postMessage("start");
worker.onmessage = function(e) {
  console.log("Worker says:", e.data);
};

// worker.js
onmessage = function(e) {
  if (e.data === "start") {
    postMessage("Heavy task done!");
  }
};

if (typeof(EventSource) !== "undefined") {
  const source = new EventSource("updates.php");
  source.onmessage = function(event) {
    console.log("Update:", event.data);
  };
} else {
  alert("SSE not supported.");
}