<!DOCTYPE html>
<html>
<body>
<h1>JavaScript 数字</h1>
<h2>BigInt typeof</h2>
<p>BigInt 的类型是：</p>
<p id="demo"></p>
<script>
let x = BigInt("9999999999999999");
document.getElementById("demo").innerHTML = typeof x;
</script>
</body>
</html>