understanding the nested for loops in javascript code example

Example 1: nested loops javascript

// Basic Javascript Nested Loop / 2D Array

for (var x = 0; x < 10; x++) {
	for (var y = 0; y < 10; y++) {
    	console.log("x: " + x + ", y: " + y);
    }
}

Example 2: nested loops js

var arr = [[1,2], [3,4], [5,6]];
 for (var i=0; i < arr.length; i++) {
  for (var j=0; j < arr[i].length; j++) {
    console.log(arr[i][j]);
  }
}