JavaScript面向对象，闭包内存图，闭包和作用域

var i = 10;
function test(){
var j;
i=20;   //未定义
function test(){
j='hello';
}
console.log(test());    //undefined
console.log(j); //hello
}
test();
console.log(i); //20

var a = 12;
var b = "12";
function c(){

}
var c = function(){
d = 15;
a = 20;
function e(){
d = 33;
}
var d;
e();
console.log(d); //33
}
c();
console.log(a); //20
console.log(b); //"12"