Change value input field according to other fields

Question

I have 10 input fields when you create a product (= node). I have an input field amount, price & reduction and sell price. So when the field amount, price & reduction are filled in I want to automatically fill in the sell price field.

Is there a module for this or should I just write some javascript to do this?

I've seen the Computed Field but I haven't tried it yet.

Answer 1

you can adopt a method like this

$(document).ready(function(){
    $('#a1').keyup(calculate);
    $('#a2').keyup(calculate);
});
function calculate(e)
{
    $('#a3').val($('#a1').val() * $('#a2').val());
}

using js