x
 
<!DOCTYPE html>
<html>
<body>
<h1>JavaScript 数字</h1>
<p>数字可以是对象,但是没有必要把数字创建为对象。</p>
<p id="demo"></p>
<script>
var x = 123;
var y = new Number(123);
document.getElementById("demo").innerHTML = typeof x + "<br>" + typeof y;
</script>
</body>
</html>