24js Number(数字)对象
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8" />
<meta http-equiv="X-UA-Compatible" content="IE=edge" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<title>Document</title>
<!-- Number对象 -->
</head>
<body>
<script>
var a = new Number("123");
var b = Number("456");
var c = 789;
var d = new Number("abc");
document.write(typeof a + "</br>");
document.write(typeof b + "</br>");
document.write(typeof c + "</br>");
document.write(d + "</br>");
</script>
</body>
</html>
