Pls i dont understand the code

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 = product *= arr[i][j];
// Only change code above this line return product; }

// Modify values below to test your code

Can someone explain the code to me?

what is it that you don’t understand?
if you explain what you understand it is easier to help you

without knowing anything I can suggest you look at your code using this tool:

We have a function that is a piece of code with name multiplyAll and one parameter arr.
We are initializing var product to 1.
for loop normally has three arguments:
we are iterating from index 0 till index of arr.length adding 1:
index: 0, 1, 2, …, arr.length-1
We have multidimensional array:
if we look at example below
index0 contains array [1,2],
index1 contains array [3,4]
index arr.legth-1 contains array [5, 6, 7]
so we need a second for loop to iterate inside of that child arrays:
form index 0 till index arr[i].lenght:
if we look at example below
arr[0] is [1,2]
we are moving forwards so:
for arr[0] => [1,2], for arr[0][0] => 1
product * 1
product is initialized to 1, it means
1 * 1
product = 1
We are going back because we can go 1 step forward till we will find arr.length
product = 1
i = 0, because we have not reached arr[i].length-1
j = 1, because we are passed calculation with j= 0
for arr[0][1] =>2, product 1
product = 1 * 2
product = 2
i = 1, j = 0, product = 2 and so we are going…
After this all process our function returns a product.

Did you take a look at the explanation given in the Guide? What part of that explanation do you not understand?

It is one mistake in code example:
// Only change code above this line return product; }
Change so:

// Only change code above this line 
return product;