前端提高篇（二十六）练习7：对象的深度克隆

注意数组和对象的判断

        var obj = {
            a:1,
            b:false,
            c:{a:2, b:true, c:{a:3, b:false}},
            d:[1,2,3,[1,2,3]],
        }
        function clone(obj){
            //数组
            if (obj instanceof Array){
                var ary = [];
                for (var i = 0; i < obj.length; i++){
                    ary[i] = clone(obj[i]);
                }
                return ary;
            }
            //对象
            if (obj instanceof Object){
                var newObj = {};
                for (var j in obj){
                    newObj[j] = clone(obj[j]);
                }
                return newObj
            }
            return obj;//如果是简单值，就直接返回
        }
        var a = clone(obj);

运行结果：当obj改变时，a不变