XInclude
XInclude is a generic mechanism for merging XML documents, by writing inclusion tags in the "main" document to automatically include other documents or parts thereof. The resulting document becomes a single composite XML Information Set. The XInclude mechanism can be used to incorporate content from either XML files or non-XML text files.
XInclude is not natively supported in Web browsers, but may be partially achieved by using some extra JavaScript code.
Example
For example, including the text filelicense.txt:This document is published under GNU Free Documentation License
in an XHTML document:
xmlns:xi="http://www.w3.org/2001/XInclude">
...
...
gives:
xmlns:xi="http://www.w3.org/2001/XInclude">
...
...
This document is published under GNU Free Documentation License
The mechanism is similar to HTML's
<object> tag, but the XInclude mechanism works with any XML format, such as SVG and XHTML.