I want to make a PDF form with various text fields.
I want to take the input from one textfield (where a number is typed in) and sustract it from another number. In the PDF, the substracted number should change based on the input from the textfield.
Is that possible? I am using \newcounter \setcounter and \addtocounter for the calculation, however I think the output from the textfield is not compatible to that. I don't know how to read the value from the textfield. Declaring a variable with \def only copies the entire textfield, how do I only get the value in the textfield? (The code output has to be opened in for example adobe acrobat reader to work)
\documentclass[a4paper,12pt,listof=leveldown]{scrreprt}
\usepackage[ngerman]{babel}
\usepackage{hyperref}
\begin{document}
\newcounter{first}
\setcounter{first}{100}
\newcounter{second}
\setcounter{second}{20} % for the 20 i have to get some value of the textbox
\addtocounter{first}{-\value{second}}\the\value{first}
\vspace{1cm}
\begin{Form}
\TextField[name=123,width=3cm,default=22,maxlen=2]{Input value:}
\def\testvalue{\value{\TextField[name=123,readonly=true,width=3cm]{}}} %define the variable
\vspace{1cm}
\testvalue %this does change when a different value is typed in above
\end{Form}
\end{document}
