how to multiple loop in javascript using for

function multiplyAll(arr) {
  var product = 1;
  // Only change code below this line
  for (var i=0; i<arr.length; i++ ){
    for (var j=0; j<arr[i].length; j++){
      product*=arr[j];
     
    }
  }
  // Only change code above this line
  return product;
}

// Modify values below to test your code
multiplyAll([[1,2],[3,4],[5,6,7]]);

let input = '1.225.441';
let isArr = input.replace(/[.]/g, '').split('').reverse();

for(let i = isArr.length - 1; i >= 0; i--) {
   let p1 = isArr[i];
   let p2 = Math.pow(10, i);
   let total = p2 * p1;
   console.log(total);
} 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]);
  }
}