## Simple If statement?

I am sure this is pretty basic, but I can't seem to get it to work. I have two form fields. One is calculated discount using some javascript, that works fine. The other is calculated profit off of that first field. I want the profit field to be calculated and populated on screen any time there is a value in the first field. So, when the page is new and blank, nothing shows, but once the discount field has been calculated the profit will show anytime you open that page.

Simple right? Can someone show me the code i need to make that happen?