The Hidden Variable dialog box enables you to insert a hidden variable into your Form or modify the existing one.
The Hidden variables are the special form fields used by script that, in its turn, processes the form. In some cases it is necessary to have parameters that cannot be changed by the web page viewer. The hidden variable is a variable of your desired type that can be used in the form, but is not displayed in browser.
To add a hidden variable, enter the Name and Value in the corresponding fields and press OK.