How do I overwrite the new values ​​from the array into the second??

I have 2 arrays (Width 100, height 10). Suppose array1 has values ​​in 2 cells, the rest are empty. Array2 has other values ​​in these 2 cells. I have a question: How to make sure that when I add new values ​​to empty cells in Array2 they are also added to Array1 in the same cells and that the old values ​​do not change the 2 occupied cells in Array1?

Here is a screenshot of how I did, but all empty cells in Array1 are filled with the same value that I add to 1 empty cell Array2.

https://drive.google.com/open?id=1BwjZxE6SToijsUvghY7JuQKo5cY7Tw2B

Try this:

Note, that saving to local storage should be outside the loop!

dop2000I tried, but the results are not recorded from Array2 to Array1. Here are screenshots of testing: