Remove 0 Value in Calculated Field

Question

I copied the below question for another post here as it asks the question perfectly.
"I set up an invoice form to calculate totals from quantity x unit price. Every line has this formula, however the users may not have a priced item on every line of the form. My total column shows a $0.00 value until I input data. I'd rather have nothing show in that column unless quantity and price are entered. Is that possible?"
However, and I apologize, but I don't understand the answer that was posted. This is the first time I've needed a calculated field -- and I've not done scripting in Acrobat before.
Can someone walk me through the exact steps of how to enter and what to enter in the form to remove "0" values from the form?
Thanks, in advance, for any and all help.

Answer 1

Thanks, again, so much. I think I got it, the procedure that is! But, but the 0 is still there.
This does now sound like a simple thing if you know the code. But apparently I'm not there yet!
This is what I did.
Under Advanced, Document Processing, JavaScript Functions.
Entered two different scripts, as follows (this is exactly how I entered them):
SCRIPT 1
Name: ds_format
Script:
function ds_format()
if (+event.value) {
//$ format for nonzero values
AFNumber_Format(2,0,0,0,"$",true);
} else {
//Don't show anything if result is zero event.value="";}
SCRIPT 2
Name: ds_keystroke
Script:
function ds_keystroke() {
AFNumber_Keystroke(2, 0, 0, 0, "$", true);
Then, under the calculated field properties (in my case, Total Cost),
Format Tab, Custom Format, Custom Format Script section, I selected edit and typed in:
ds_format();
Ditto above, but under Custom Keystroke Script:
ds_keystroke();