对象的深度克隆

function clone(obj) {
        var buf;
        if(obj instanceof Array){  //被克隆的对象是数组
            buf = [];
            var i = obj.length;
            while(i--){
                buf[i] = clone(obj[i]);
            }
            return buf;
        }else if(obj instanceof Object){  //被克隆的对象是对象
            buf = {};
            for (var k in obj){
                buf[k] = clone(obj[k]);
            }
            return buf;
        }else{
            return obj;    //被克隆的是普通类型
        }
    }
    
    
    function F (){
        this.name = "liu",
        this.color = ["red","green"],
        this.friends = {
            first : "yangyi",
            second : "koukou"
        }
    }
    var f = new F();
    var fClone = clone(f);
    console.log(fClone.friends);  //{first: "yangyi", second: "koukou"}
    console.log(fClone.colors);  //["red","green"]
    console.log(fClone.name);    //"liu"