lovecoding
/
W0407


			
				
					
						
						
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    <script>
        /**
         * js的数据类型：
         * 基本数据类型
         *  Null Undefined String Number Boolean
         * 引用数据类型
         *  Object(函数 对象 数组)
        */
        var obj = { name: "图图" };
        var arr = [1, 2, 3, 4];
        function fn1() { return 1 };

        //    // 1.typeOf()
        //    console.log(typeof(1));
        //    console.log(typeof("1"));
        //    console.log(typeof(true));
        //    console.log(typeof(undefined));
        //    console.log(typeof(null));
        //    console.log(typeof(obj));
        //    console.log(typeof(arr));
        //    console.log(typeof(fn1));

        //2. instanceof 
        // console.log(obj instanceof Object)
        // console.log(arr instanceof Array)
        // console.log(fn1 instanceof Function)

        // 3.Object.prototype.toString.call(xxx)
        // console.log(Object.prototype.toString.call(1));
        // console.log(Object.prototype.toString.call("1"));
        // console.log(Object.prototype.toString.call(false));
        // console.log(Object.prototype.toString.call(null));
        // console.log(Object.prototype.toString.call(undefined));
        // console.log(Object.prototype.toString.call(obj));
        // console.log(Object.prototype.toString.call(arr));
        // console.log(Object.prototype.toString.call(fn1));

        // 4.constructor
        // null undefined无法判断
        console.log(false.constructor === Boolean);
        console.log('false'.constructor === String);
        console.log((21).constructor === Number);
        // console.log(null.constructor === Null);
        // console.log(undefined.constructor === Undefined);
        console.log(obj.constructor === Object);
        console.log(arr.constructor === Array);
        console.log(fn1.constructor === Function);
    </script>
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