lovecoding
/
Web1020


			
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							<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <script>
        // 基本数据类型
        var num = 1;
        var str = 'hello';
        var bool = true;
        var oNull = null;
        var oUndefined = undefined;
        // 引用数据类型
        var arr = [1,2,3,4,5];
        var obj = {};
        var foo = function(){};

        // typeof 可以判断基本数据类型 返回字符串
        // console.log(typeof num);
        // console.log(typeof str);
        // console.log(typeof bool);
        // console.log(typeof oNull);
        // console.log(typeof oUndefined);
        // console.log(typeof arr);
        // console.log(typeof obj);
        // console.log(typeof foo);

        // instanceof 可以判断引用数据类型 返回布尔值
        // console.log(arr instanceof Array);
        // console.log(obj instanceof Object);
        // console.log(foo instanceof Function);
        // console.log(num instanceof Number); 

        // cunstructor 可以判断引用数据类型 返回构造函数
        // Array, Object, Function, Number, String, Boolean
        // console.log(arr.constructor);
        // console.log(obj.constructor);
        // console.log(foo.constructor);
        // console.log(num.constructor);
        // console.log(str.constructor);

        // Object.prototype.toString.call() 可以判断所有数据类型 返回字符串
        console.log(Object.prototype.toString.call(num));
        console.log(Object.prototype.toString.call(str));
        console.log(Object.prototype.toString.call(bool));
        console.log(Object.prototype.toString.call(oNull));
        console.log(Object.prototype.toString.call(oUndefined));
        console.log(Object.prototype.toString.call(arr));
        console.log(Object.prototype.toString.call(obj));
        console.log(Object.prototype.toString.call(foo));


    </script>
</body>
</html>