Age calculator

Hello hackers,

This is my solution to the age calculator challenge.

I have the following issues, if i click submit when the input forms are empty, I see the error message and then if I add some values in the input and reclick submit the app calculates a false date. I tried to understand why does it happen but I still can't get it.

Then I saw that the app works one time then I have to refresh the page again to make it work. I suppose that I need to use a load or ready function?

Any suggestions, tips are really welcome

Thanks in advance :) Kind regards Eli