在Object基本类定义的这个toString()方法，是用来检测数据类型的；
在JS内：
console.log(Object.prototype.toString.call(1));//[object Number]
console.log(Object.prototype.toString.call(''));//[object String]
console.log(Object.prototype.toString.call(true));//[object Boolean]
console.log(Object.prototype.toString.call(null));// [object Null]
console.log(Object.prototype.toString.call(undefined));//[object Undefined]
console.log(Object.prototype.toString.call([]));// [object Array]
console.log(Object.prototype.toString.call({}));// [object Object]
console.log(Object.prototype.toString.call(/^$/));//[object RegExp]
console.log(Object.prototype.toString.call((function () {})));//[object Function]