<!DOCTYPE html>
<html>
<head lang="en">
<meta charset="UTF-8">
<title>数据类型</title>
<script>
var age = 20; //number 数值类型
// alert(typeof(age));
document.write("变量 var age =20 数据类型是 :"+typeof(age) +"
"); //将write函数括号内的值显示到html页面
var user = "小明"; //string 字符串类型
document.write("变量 var user = '小明' 数据类型是 :" + typeof (user) +"<br/>");
var sex = true; //boolean 布尔类型
document.write("变量 var sex = true 数据类型是 :" + typeof (sex) +"<br/>");
var is;
document.write("变量 var is; 数据类型是 :" + typeof (is) +"<br/>");
var isnull = null; //object 对象类型
document.write("变量 var isnull = null :" + typeof (isnull) +"<br/>");
</script>
</head>
<body>
</body>
</html>
