Object reference (deep, shallow copy)

This existence referential relationship var a=[1,2,3];            var b=a;            B.push (4); alert (b);//1,2,3,4 alert (a);//1,2,3,4//This does not have a referential relationship//b re-assigned value will reopen an address var a=[1,2            , 3];            var b=a;            b=[1,2,3,4];            alert (b);//1,2,3,4 alert (a);//1,2,3 var obj1={a:10};            var obj2=obj1;            obj2.a=20;                        alert (obj1.a);//20;            var obj1={a:10};                function copy (obj) {//Shallow copy var newojb={};                for (var attr in obj) {newojb[attr]=obj[attr];            } return NEWOJB; }
If the above is Var obj1={a:{b:10}} It is necessary to perform deep lookup function deepcopy (obj) {//Deep copy var newojb={};                                if (typeof obj1! = "Object") {//Termination condition return obj1;//returns the original 10}                for (var attr in obj) {newojb[attr]=deepcopy (obj1[attr]);//recursive}            return NEWOJB;            } var obj2=copy (obj);            obj2.a=20; Alert (obj1.a)//10

Object reference (deep, shallow copy)