Differences between JS traversing arrays and objects and details of how to recursively traverse objects arrays and attributes

Say nothing more, go straight to the topic, you, the code is as follows:

<script>
 //----------------for Used to traverse array objects --
 var i,myArr = [1,2,3];
 for (var i = 0; i < myArr.length; i++) {
  console.log(i+":"+myArr[i]);
 };
 //---------for-in  Used to traverse non-array objects 
 var man ={hands:2,legs:2,heads:1};
 // Add for all objects clone Method, i.e. giving built-in prototypes (object,Array,function) Add Prototype Properties , This method is powerful and dangerous 
 if(typeof Object.prototype.clone ==="undefined"){
  Object.prototype.clone = function(){}; 
 }
 //
 for(var i in man){
  if (man.hasOwnProperty(i)) { //filter, Output Only man Private property of 
   console.log(i,":",man[i]);
  };
 }
 // The output is print hands:2,legs:2,heads:1
 for(var i in man) {// Do not use filtering 
  console.log(i,":",man[i]);
 } 
 // The output is 
 //hands : 2 index.html:20
 //legs : 2 index.html:20
 //heads : 1 index.html:20
 //clone : function (){} 
 for(var i in man) {
  if(Object.prototype.hasOwnProperty.call(man,i)) { // filter 
   console.log(i,":",man[i]);
  }
 } // The output is print hands:2,legs:2,heads:1 </script>

Next, we introduce js recursive traversal of objects, arrays, attributes

When working on the front end, sometimes we need to traverse an object of unknown type.The code is as follows:

//js traversal object
function TraversalObject(obj)
{
for (var a in obj) {
if (typeof (obj[a]) == "object") {
TraversalObject (obj [a]); //Recursive traversal
}
else {
alert (a +'='+ obj [a]);//Value is displayed
}
}
}

//Traverse all Ur values in the object
function TraversalObject(obj)
{
for (var a in obj) {

if (a=="Url") alert (obj[a]); / /Show the value of URL
if (typeof (obj[a]) == "object") {
TraversalObject (obj [a]); //Recursive traversal
}
}
}

This traversal method works well when objects are irregular but need to acquire the same attributes.