length of list in 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 5var colors = ["Red", "Orange", "Blue", "Green"];
var colorsLength=colors.length;//4 is colors array length 

var str = "bug";
var strLength=str.length;//3 is the number of characters in bugvar nums = new Array();
nums[0] = 1; 
nums[1] = 2;
print(nums.length); // displays 2