how to read length of array in js code example

Example 1: array length javascript

var arr = [10,20,30,40,50]; //An Array is defined with 5 instances

var len= arr.length;  //Now arr.length returns 5.Basically, len=5.
console.log(len); //gives 5
console.log(arr.length); //also gives 5

Example 2: array length in js'

var x = [];
  console.log(x.size());
  console.log(x.length);
  console.log(x.size()==x.length);
  x =[1,2,3];
  console.log(x.size());
  console.log(x.length);
  console.log(x.size()==x.length);
//arjun