thats a school's exercise i have to do, but i don't know why it doesn't work. could someone help me?

Question

so the exercise asks to make a sum of 2 numbers using the forms, and wants that those 2 numbers are shown in an alert using a button(i don't know why but can't use the 'submit')
here is a picture of how the exercise is supposed to look: https://ibb.co/Wz3jx5z ( it's wrote in italian so i'm going to translate: uno, due, .. , cinque simply means 1,2, .., 5. while "invia il" mens "send the").
here is the code that i have made: https://code.sololearn.com/WA14A10A2381/#
, the function or the button doesn't work. which is the problem?

Answer 1

first error is syntax of 'function' wich should not be capitalized...

however, there are some logical errors:

id are supposed to be unique...
in case of multiple elements with same id, only the first one is returned, so you'll always get 1 and 1... as string (so result of n1+n2 is '11').

you need to get (and cast to number) the select value for n1, and the #N2:checked value for n2... using querySelector will help:

https://code.sololearn.com/WA23A22a135A/?ref=app

Answer 2

Thanks visph but how does the .querySelector works?

Answer 3

querySelector get one string argument wich is the css selector string of targeted element... it return the first element matching it.

querySelectorAll works same, but return an array-like of all matching elements...

both are available on document and every node elements ;)

Answer 4

https://www.javascripttutorial.net/javascript-dom/javascript-queryselector/

Answer 5

visph and select and checked? Couldnt write in the First One "#N1:checked"?
edit:
maybe i understand, the queryselector automaticcally takes the First id so for add the second id to the variable Need to use the "#N2:checked"

Answer 6

no: :checked pseudo class is only available for radios/check boxes... select works differently, and hold selected value directly on select element ;)

Answer 7

visph thanks for everything at school they basically give tasks without explaining that much, you been a lot more helpful than my teacher

Answer 8

you're maybe expected to do some research by your own ;P

however, I don't know if you are supposed to use anything else than simple <input type="text" id="Nx"> (or type="number"), from wich you could get value just by +getElementById('Nx').value ^^

Answer 9

visph i must use the radio and the other type I don't remember right now