The difference between JSON and array

JSON is a data format in JavaScript that resembles an array, but differs from an array in that it differs from the subscript :

For example, Var obj=[a:15,b:10,c:3,d:8];//This is the notation for JSON

var arr=[15,10,3,8]; This is the notation of the array

As can be seen, each element in the JSON is a string as subscript: A,b,c,d, and the array is a number as subscript, 0,1,2,3

There are two methods of array looping :

1) Normal for loop

2) for in:

var i=0;

For (i in arr) {.... }

For arrays, the for loop is more flexible because it can change the position of the starting loop, such as i=1,2,3, and the For in loop cannot be changed, but can be looped from beginning to end,

json loop method : Just can use the for

such as: for (i in obj) {... }

The difference between JSON and array