How do I validate an input in elixir?

Question

I am trying to write tests using hound and elixir and I cant seem to figure out a way to validate what was input into an input field... There is obviously a way to do this, but I have not figured out how to do so....

Example:

<input type="number" xpath="1" style="">

If I input 1 into this, how can I check that the field contains a 1?

I have been trying this method:

execute_script("document.querySelector(arguments[0]).value;", [
          "input[type='number']"
        ])

and this is giving me "nil"