I\'m trying to understand where is my error, because it\'s not possible that JS fails in math!
On the HTML form I have a select and 9 text input. Then, on the JS I c
Because you're comparing strings, not integers. Use parseInt to explicitly cast your values as integers.
Here's essentially what you're doing: jsFiddle example
To do the conversion, change your variables to something like:
var new_da1 = parseInt( document.getElementById('new_da1').value, 10);
(assuming they're all integers)