Read Acrobat format actions when detecting fillable fields

Featurekamo-internal
Shipped
August 5, 2026 at 11:52 PM UTC
Author
kamo
Commit
743b438

Acrobat stores a field's intended format as JavaScript in /AA, which pdf.js surfaces as actions.Format. That is the author's declaration rather than a guess off the field name, so it now outranks the name/caption heuristic: - AFNumber_Format -> currency when it carries a currency string, else number - AFDate_Format/AFDate_FormatEx -> date, AFTime_Format -> time - AFPercent_Format -> number - AFSpecial_Format(n) -> zip / zip+4 / phone / SSN - a Calculate action means the field is computed, so it imports read-only Also: a signature or initial widget thinner than the control needs now grows upward from its bottom edge, since a PDF signature field is often only as tall as the printed rule it sits on and ink belongs above the line; and a pure XFA document is reported as such instead of reading as "no fillable fields", because its fields live in XML that AcroForm detection cannot see. Verified against real pdf.js 4.10.38 alongside the unit suite.

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