深拷贝

                function deepClone(origin, target){
            var tar = target || null
            var str = Object.prototype.toString
            for(var key in origin){
                if(origin.hasOwnProperty(key)){
                    if(typeof origin[key] === 'object' && origin[key] !== null){    
                        tar[key] = str.call(origin[key]) === '[object Array]' ? [] : {}
                        deepClone(origin[key], tar[key])
                    }else{
                        tar[key] = origin[key]
                    }
                }
            }
            return tar;
        }