Scripts in Documents

Some PDF forms carry small programs (JavaScript): totals that calculate themselves, checks on what you type, fields that fill in when the form opens. DocuWrit can run them — but a document does not get to run code just because you opened it.

The yellow bar

When a document contains scripts, it opens with them switched off and a bar above it:

Scripts are off until you say otherwise

Choice	What happens
Run scripts	The document's scripts run until you close its tab. Next time it asks again.
Always for this document	Runs them now and every time you open this file. Offered once the document has been saved to a file.
x	Leaves the scripts off. You can still read the document and fill in its fields; calculated fields just stay empty.

Anything you typed before switching scripts on is kept. Documents without scripts never show the bar.

Changing the rule

DocuWrit menu > Scripts in documents:

• Ask before running them — the yellow bar (the default).
• Always run them — every document's scripts run without asking.
• Never run them — scripts stay off and no bar is shown.

A change applies to documents opened from then on.

Where “Always for this document” is remembered

In your Windows user profile, as a list of file locations — not inside the PDF. That means:

• it applies to you on this PC only; sending the PDF to someone does not send your trust with it;
• moving or renaming the file makes DocuWrit ask again;
• the list keeps the last 100 documents; older ones ask again.

What a script can and cannot do

Scripts run in a sandbox, a sealed box inside the viewer — the same design the Firefox browser uses for PDF forms.

A script can	A script cannot
read and change the form's own fields; show a message box; ask the viewer to print, zoom or turn the page	read or write files on your computer; use the network or the internet; open web pages; start programs; reach other documents or DocuWrit itself

Two more safeguards:

• A script cannot save silently. If a script asks for the document to be saved, DocuWrit asks you first.
• Links never load inside DocuWrit. A web link in a document opens in your web browser, where your browser's protections apply.

Seeing and changing the scripts of a document

Form Fields > Scripts lists all the JavaScript stored in a PDF, whoever made it: document scripts (they run when the document opens), document and page actions, and the scripts of every field — format, keystroke, validate, calculate, button and mouse scripts. Select one to read it. You can change it, delete it, rename a document script, add a new document script, or add a document action (before / after saving and printing, before closing).

Form Fields > Scripts: every script of the document

• Nothing is run in this window. Scripts are shown, checked and saved — reading a suspicious document's scripts here is safe.
• Scripts you do not touch stay exactly as they are, byte for byte.
• A field's own scripts are easier to add in the field's properties (Format, Calculate and Actions tabs): see Build fillable forms.

The script check

Every script is checked when you leave it, when you press Check script, and before the document is changed:

Finding	Example	What happens
Syntax error	a missing bracket: “Validate script, line 1: Unexpected token '{'”	The script cannot be saved until it is fixed.
Warning: web-page code	alert(...), window, document, console.log, setTimeout, fetch — none of these exist in a PDF. The message names the PDF way: app.alert(...), this.getField(...), console.println(...).	DocuWrit lists the warnings and asks whether to save anyway.
Warning: a field that does not exist	getField("Totl") — “Did you mean "Total"?”
Warning: newer JavaScript	arrow functions, let / const, template literals: they run in DocuWrit but may not run in older versions of Acrobat.
Warning: a call DocuWrit ignores	calls that open web pages or files, send mail or data, or save the document

The check reads the script; it does not run it and cannot promise that the script does what you meant. Test the form with scripts switched on.

When a field's scripts run

The scripts of a field run when you leave the field — with Tab, by clicking somewhere else on the page, or by clicking anywhere else in DocuWrit. A read-only field that a script fills in (a total, a barcode) is redrawn at once, in its own font, exactly as it will be saved and printed.

Next: Shortcuts & Troubleshooting.