一，js代码:
<html>
<head>
<meta charset="utf-8"/>
<title>测试</title>
</head>
<body>
<script>
//一，用typeof 得到变量的类型
let one = 'a';
console.log(typeof one);
one = 1;
console.log(typeof one);
one = true;
console.log(typeof one);
one = Symbol();
console.log(typeof one);
one = undefined;
console.log(typeof one);
one = new Function();
console.log(typeof one);
//二，用toString.call得到变量的类型
one = 'a';
console.log(typeof one);
console.log(toString.call(one));
one = 1;
console.log(typeof one);
console.log(toString.call(one));
one = true;
console.log(typeof one);
console.log(toString.call(one));
one = Symbol();
console.log(typeof one);
console.log(toString.call(one));
one = undefined;
console.log(typeof one);
console.log(toString.call(one));
one = new Function();
console.log(typeof one);
console.log(toString.call(one));
//说明：可以看到 对象,null,数组,Date,Error等被typeof统一识别成 object
// 这种情况下使用toString.call更准确
one = null;
console.log(typeof one);
console.log(toString.call(one));
one = {};
console.log(typeof one);
console.log(toString.call(one));
one = [1,2,3];
console.log(typeof one);
console.log(toString.call(one));
one = new RegExp();
console.log(typeof one);
console.log(toString.call(one));
one = new Date();
console.log(typeof one);
console.log(toString.call(one));
one = new Error();
console.log(typeof one);
console.log(toString.call(one));
one = window;
console.log(typeof one);
console.log(toString.call(one));
one = document;
console.log(typeof one);
console.log(toString.call(one));
//三，用instanceof判断是否某个类的实例:
function A(name,age){
this.name = name;
this.age = age;
}
let a = new A('张三',18);
console.log(a instanceof A);
class myClass{
constructor(name,age){
this.name=name
this.age=age
}
}
let i=new myClass('小明',18);
console.log(i instanceof myClass);
console.log(i instanceof A);
console.log(typeof i);
console.log(toString.call(i));
//四，constructor方法，因为不支持undefined和null,不再举例
</script>
</body>
</html>
说明：刘宏缔的架构森林是一个专注架构的博客，地址：https://www.cnblogs.com/architectforest
对应的源码可以访问这里获取： https://github.com/liuhongdi/
或: https://gitee.com/liuhongdi
说明：作者:刘宏缔 邮箱: [email protected]
二，测试效果
三，查看chrome的版本:
标签：5195.125,console,log,chrome,javascript,toString,typeof,new,call From： https://www.cnblogs.com/architectforest/p/16758567.html