Native XFA Field Defaults

A field whose data node is missing reads its native form value or its template value child; a field with an existing empty data node stays empty

This behavior applies to implicit binding, explicit dataRef binding and fields with bind match="none", using the existing binding resolver to identify each dataset occurrence

Missing and empty values

For a template text default of seed, a missing data element displays seed, an existing empty element displays an empty value, and a data element containing first displays first

Reading or saving a default-backed field does not manufacture dataset nodes; explicitly clearing the field creates or updates its writable instance value, which stays empty after native XDP reload

Instance isolation

Interactive widget commits and calculation results write to instance data or a separate native form value, preserving the shared template default

Repeated fields resolve defaults within their own occurrence context; editing one occurrence preserves the values of its siblings

Failed scripts restore the native transaction snapshot, including the original absence of the data node and the displayed default

Saved PDF output

XFA AcroForm conversion consumes the same value resolver for native field values and generated appearances; editable and read-only conversions retain the correct missing and empty values

Conversion preserves complete SOM bind resolution and the existing form-packet emission lookup; occurrence-specific form and template defaults supply values when the binding or emission lookup has no value

The focused acceptance producer saves initial, explicitly cleared and read-only PDFs; independent pypdf and MuPDF checks inspect field values, native flags, visible text and the associated XDP packets

Related APIs

HPDFXFAResolveFieldValueNode, Native Data DOM and Interactive Dynamic XFA Widget Runtime