第一部分 什么是 XFA？
XFA：XML Forms Architecture
XML：
extensible markup language(
可扩展标记语言)
XFA is similar to PDF interactive forms introduced in PDF 1.2, which is also known as AcroForm,
with the following differences:
● XFA can be used in XML-based workflows.
● XFA separates data from the XFA template, which allows greater flexibility in the structure of
the data supported and which allows data to be packaged separately from the form.
● XFA can specify dynamically-growing forms.
● XFA can specify Web interactions, such as HTTP and Web Services (WSDL). Such interactions
can be used to submit data to a server or to request a server perform a calculation and return the
result.
● XFA works with other XML grammars.
