http://sinhviencntt.net/hoc-javascript-bai-12-cac-kieu-du-lieu-trong-javascript/http://sinhviencntt.net/hoc-javascript-bai-12-cac-kieu-du-lieu-trong-javascript/
http://sinhviencntt.net/hoc-javascript-bai-12-cac-kieu-du-lieu-trong-javascript/
by sinhviencntt
HTML
<!DOCTYPE html>
<html>
<body>
<p id="demo"></p>
<script>
var x = "";
document.getElementById("demo").innerHTML =
"Giá trị là: " +
x + "<br>" +
"Kiểu dữ liệu là: " + typeof x;
</script>
</body>
</html>