js 作用域的问题

//a(); //is not a function

var a=function(){

console.log("111");

}

a(); //111

b(); //222

function b(){

console.log("222");

}

console.log(params.name);

var params={

name: "xiaoming"

}

console.log(params.name); //xiaoming

var F=function(){};

Object.prototype.a=function(){};

Function.prototype.b=function(){};

var f=new F();

console.log(f.a); //function (){}

console.log(f.b); //undefined

var a={n:1};

var b=a;

a.x=a={n:2};

console.log(a.x); //undefined

console.log(b.x); //Object {n: 2}