When you click on a variable icon (orange triangle), you will see a list of all variables that are present in the system. Variables that are used in the current context (e.g. the current Profile) appear at the top. You may pick any of the existing variables (1), create a new one (2) or edit one that is already assigned (3).

As you may have seen, there are two different types of variables:

A simple variable can be inserted into a parameter of e. g. a Check to make it dynamic. When the Check is run in pdfToolbox Desktop, the software asks the user which value to insert for the variable.

Script variables are defined in the form of a JavaScript; this allows deriving the value for a variable from other variables, from the metadata of the current PDF file, or from the results of a previous preflight Check. If you want to learn more about script variables then you can find everything in the next article: Variables using JavaScript: Overview

To define a variable pdfToolbox needs at least three pieces of information: key, label and default value.

1. Key:  for internal use and use on the command line to address the variable (therefore the key should be unique).
2. Label: for use in the user interface, for example in the "Ask at runtime" dialog.
3. Type: Simple value (simple variable) or Script (JavaScript-based variable). Tip: on the right side the value type is always specified, which must be used for the default value. The following types are available (Float, Sting, Boolean, Pop-up, Integer).
4. Default value: to be used unless a different value is provided at runtime.
5. Allow Browser button in feasible: determines whether a browse button is displayed in the Ask-at-runtime dialog when executed in pdfToolbox Desktop, allowing the user to select a file from the system (e.g. to load an ICC profile).
6. Limit input values to specific values: you may define restrictions (this is explained in a later step in this chapter).
7. Show evaluation results: if enabled, a console will be available for debugging.

If the parameter for which a variable is to be created is a Checkbox or a PopUp, only predefined values are valid for the default value:

A checkbox has the value type Boolean, which means that only two default values are valid: 0 (checkbox is disabled) or 1 (checkbox is enabled). Other values are not valid.

The value type PopUp has always an info button in the variable editor, which contains all valid values. The example below shows the default values for the severities of a Check. You can choose between 4 severities: Inactive, Info, Warning, Error. Depending on which severity is selected in the info dialog, the appropriate default value is added to the variable. In our example the severity should be "Error" as default, which has the default value 3.

Constraints can be defined by using the "Limit input values to specific values" checkbox in the variable editor. There are two ways to limit the input values: the value provided for the variable can be limited to a range, or it can be limited to a list of predefined values.

It is possible to define a variable as a step in a Process Plan. This will work similar to a variable on Profile level and is only useful and effective for script variables.

Deleting a variable is currently only possible in the Library Manager (Library drop down> Manage Libraries) and only if the variable is not used. Via the info button you can see in which Profiles the variable is used.

In pdfToolbox Desktop a dialog shows up, when a Profile/Check/Fixup/Process Plan is executed that has one or more variables – the so called "Ask-at-runtime" dialog. Further information about the Ask-at-runtime dialog can be found here: Ask-at-runtime Dialog: Introduction.