var num = 1;

alert(Object.prototype.toString.call(num)); // [object Number]

var str = 'hudidit.com';

alert(Object.prototype.toString.call(str)); // [object String]

var boo = true;

alert(Object.prototype.toString.call(boo)); // [object Boolean]

var fun = function(){};

alert(Object.prototype.toString.call(fun)); // [object Function]

var obj = {};

alert(Object.prototype.toString.call(obj)); // [object Object]

var arr = [];

alert(Object.prototype.toString.call(arr)); // [object Array]

var n = null;

alert(Object.prototype.toString.call(n)); //[object Null]

var u = undefined;

alert(Object.prototype.toString.call(u));//[object Undefined]