a Java applette designed to display XML content embedded in traditional HTML documents.. The XML contents may either be authored into the HTML document explicitly (as when the XML is authored concurrently with the HTML document), or the XML content may be unknown implicit (as when the XML document is imported). In the first case it may be beneficial for the XML elements to inherit the style properties of the parent HTML document (e.g. via. Inheritance from the parent style properties or ID and CLASS attributes), in the second case the XML content should probably be "hidden" from the parent document. There may be multiple XML documents within the HTML document. A wrapper may use one or more "extracters" to extract data from unstructured XML files. Extractors utilize dictionaries to achieve sophisticated lingustic processing of unstructured text. Life is much easier for structured documents having XML markups. An illustration in terms of a web shopping guide is provided on Page 136 of The XML Handbook by Charles F. Goldfarb and Paul Prescod (ISBN 0130811521, Prentice-Hall Computer Books, 1998). Note that the issue of using an XML wrapper is quite different from using an XML compliant browser. One such wrapper uses <XMLDOC> tags. In XML, a tag beginning with the sequence XML is not allowed as these tags are reserved. XMLDOC however is not an XML tag it is an HTML tag.
Related to a wrapper is the concept of an XML "extractor" for generating XML from HTML documents and databases having no XML markups. In building a XML markups, we need to provide a way for the tool to generate XML documents from existing data sources. XML markup assembly is a process of locating data (e.g., product attributes) in repositories and merging them into an XML structure that is consistent with the some predefined schema. Asset repositories can be of various types (databases, filesystems, etc.) and the details of how information is retrieved from them may differ considerably. Life is much easier if the data sources have a fixed document type definition ( DTD ). An illustration is provided in Chapter 9 of The XML Handbook by Charles F. Goldfarb and Paul Prescod (ISBN 0130811521, Prentice-Hall Computer Books, 1998). In that illustration, the Junglee Shopping Guide extracted XML markups from book seller web sites that did not have XML tags.
Also see HTML and Resource Description Format .