实现type函数用于识别标准类型和内置对象类型

function type(obj){
return Object.prototype.toString.call(obj).slice(8,-1);
}

var t=type(new Number(1)); console.log(t); 
var t=type("abc"); console.log(t);
var t=type(new String("abc")); console.log(t);
var t=type(true); console.log(t);
var t=type(undefined); console.log(t);
var t=type(null); console.log(t);
var t=type({}); console.log(t);
var t=type([]); console.log(t);
var t = type(new Date);console.log(t);
var t = type(/\d/);console.log(t);
var t = type(function(){});console.log(t);