Need Help by some % calculation

Question

Hi Guys,
i need some help calculating something.
I have 5 boxes; "boxA" - "boxB" - "boxC" - "boxD" and "boxE". Box A–C are sums coming from other fields.
"boxD" represent the VTA – and can be just 19% ore 0%.
This means that "boxE" = ("boxA" + "boxB" + "boxC") * "boxD" ("box D" is equal with 0,19  – if the customer types 19% in the field – ore "0" (zero) – by leaving the "boxD" empty or typing the value "0" inside. A multiplication with 0 would be false, so it had to be ignored if the content of the "boxD" is 0)
I suppose it will be something with "if" and "else" but how i say, I'm a greenhorn in this domain.
Actually i found something that could help but i thing some parts – the definition of var v4, if v4 get the value 19% ore 0% – are missing.
(function() {
   // Get the field values, as numbers
   var v1 = +getField("boxA").value;
   var v2 = +getField("boxB").value;
   var v3 = +getField("boxC").value;
   var v4 = +getField("boxD").value;
    // I suppose here comes some "if" "else" stuff for the definitoon of var4
   // Perform the calculation; the result is the content of the "boxE"
   var result = v4 * (v1 + v2 + v3);
   // Set the value of this field to the result
   event.value = result;

Answer 1

I would make sure you are not having a problem with using the "," as the decimal separator.
What problem are you having?
Is there an error in the JavaScript console?
If so, what is the exact wording?
Have you examined the values within the script to make sure you are getting the value you are expecting?