জাভাস্ক্রিপ্ট hasFocus

<!DOCTYPE html>
<html>
<body>

<button onclick="check()">ফলাফল</button>

<p id="result"></p>

<script>
function check() {
  result.textContent = document.hasFocus() ? "ফোকাস" : "";
}
</script>

</body>
</html>