When you last used Adobe Acrobat to build a PDF form document, you may have started with a Word document that you saved to PDF, and then used Acrobat to add text fields, check boxes, radio buttons, a bar code, a digital signature, and other form field elements. You probably didn’t think about the technology behind the format, which is fine, because now you won’t need to.
PDF form documents can use two format types, Adobe Acrobat Forms, or AcroForms, and XML Forms Architecture, or XFA. Adobe developed AcroForms in 1998. AcroForm is the original PDF forms technology and it remains the primary method for building PDF forms documents today. XFA is a set of proprietary XML specifications for use with web forms. Adobe also owns the XFA format, and XFA forms can be saved internally in PDF files. Unlike AcroForms, XFA forms can allow text reflow, so that text fields can resize to allow more content if needed. Dynamic XFA forms can also be interactive, as the form document is built using a series of templates. The form document can respond to the information that a user enters or selects and display a different set of form fields relevant to the user’s answer.
In 2020, however, most PDF documents use AcroForms technology. XFA is complex and requires special software from Adobe; the LiveCycle Designer. But Adobe no longer sells LiveCycle as a part of Adobe Acrobat and has replaced it with a new content management system called Adobe Experience Manager, which is designed to convert XFA forms into HTML. In years past, a variety of third-party applications were built to work with the XFA standard in PDF documents, but over time, PDF documents with embedded XFA forms have become increasingly isolated because few software products remain that support that format. Commonly, a PDF form using XFA can be opened and viewed in Acrobat, but not edited. Users who try to open an XFA form in a viewing tool that is not specifically designed to interpret XFA will see an error message. AcroForms are compatible with a much wider range of software applications, as well as with Acrobat itself. Further, XFA was deprecated in the new PDF 2.0 format and is not permitted for use with special ISO formats for PDF documents such as PDF/A, or PDF Archive. Google Chrome and most other browsers will not display XFA documents, and XFA is not supported on mobile devices.
Meanwhile, the dynamic field capacity of XFA forms is the only feature that XFA offers that is not available in AcroForms. The excellent support for JavaScript in AcroForms allows you to make an AcroForms form document interactive if that’s what you need. Additionally, you can’t properly print a PDF form using XFA if the fields are expanded, as the extra characters entered in the fields won’t show up on paper.
The XFA format is being phased out, and the standard for managing forms within PDF files in the future will be AcroForms. We point this out because there still are some users who work with XFA form technology, and we have tools available that were designed to manage and convert XFA form documents. But if you are going to be building or manipulating PDF forms documents programmatically in the future, knowing to rely on AcroForms rather than XFA is important. At Datalogics, we can help with our command-line tool PDF Forms Flattener.
Have questions about how to work with XFA & AcroForms? Don’t hesitate to contact us today!
