javascript set get

var a = {
   v: "xxx",
   get aa(){//不用写function和:
       return this.v+"!"
   },
    set aa(v){//不用写function和:
       return this.v = v
   }
}
a.aa = 2
console.log(a.aa )
>> 2!

ES5的 ie下.....你懂的