On several cloning (clone) methods in JavaScript

Clone is to copy the original thing as it is, and the new copy has nothing to do with the previous thing.

A: In JavaScript, if the cloned object is a basic type, we can assign it directly:

var sStr = "Kingwell";   var cStr = sStr;   alert (CSTR); // Output Kingwell   SSTR = "abc";  alert (CSTR); //

When you assign a value to another variable, the value of that variable is not affected when it is changed.

It is important to note that the copy will copy the value of the A object to B, because it is the basic type, this value no longer points to other places, so when the value of a changes, the value of B will not change, but if the assignment is the object, the case is different, although the value of a is copied to B, but this value points to the The real content is stored in the heap memory, so when a object changes the content, the content of the B point changes.

Two: If it's not the basic type, it's all different:

var aarr = [0,1,2,3];   var m = aarrr;  Alert (m); // Output   aarr=[1,1,2,3];  Alert (m); // output 1,1,2,3; This value is changed because M is only a reference to Aarr, and if the value of Aarr is changed, then M will change accordingly.  

If we want to clone an array, the simplest way:

var aarr = [0,1,2,3];   var m = aarr.slice (0);   = [3,2,1,0];  Alert (m); //

We can create a function to clone all objects:

functionClone (obj) {varo; if(typeofobj = = "Object") {          if(obj = = =NULL) {o=NULL; } Else {              if(objinstanceofArray) {o= [];  for(vari = 0, len = obj.length; i < Len; i++) {O.push (Clone (Obj[i))); }              } Else{o= {};  for(varJinchobj) {O[j]=Clone (Obj[j]); }              }          }      } Else{o=obj; }      returno; }  

Three: node cloning:

var p = document.getelementsbytagname ("P") [0];   var cP = P.clonenode (); // clone p node   var cP = P.clonenode (true); // clone p node, deep clone, clone node and sub-content under node.  

On several cloning (clone) methods in JavaScript