<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>变量的类型</title>
</head>
<body>
<script type="text/javascript">
//javascript原始数据类型：
// undefined null number boolean string
var v; //只声明，没赋值
document.write(v);
document.write("<br/>")
var v1 = null;
document.write(v1)
document.write("<br/>")
var v2 = 100;
document.write(v2)
document.write("<br/>")
var v3 = false;
document.write(v3)
document.write("<br/>")
var v4 = "hello";
document.write(v4)
//javascript当中表示字符串，可以使用单引号，也可以使用双引号。
document.write("<br/>")
var v5 = 'world!!';
document.write(v5)
document.write("<br/>")
var v6 = 3.14;
document.write(v6)
//javascript引用数据类型： object
var obj = new Object();
document.write("<br/>")
document.write("----------类型判断方法--------------<br/>")
document.write(typeof(v))
document.write("<br/>")
document.write(typeof(v1))
document.write("<br/>")
document.write(typeof(v2))
document.write("<br/>")
document.write(typeof(v3))
document.write("<br/>")
document.write(typeof(v4))
document.write("<br/>")
document.write(typeof(v5))
document.write("<br/>")
document.write(typeof(v6))
document.write("<br/>")
document.write(typeof(obj))
document.write("<br/>")
</script>
</body>
</html>
