Welcome

This project exposes the custom XHTML element w3-include-xhtml as defined by the DTD extension:

                        <!ELEMENT w3-include-xhtml EMPTY>
                        <!ATTLIST w3-include-xhtml href CDATA #REQUIRED>
                    

Example:

                        <w3-include-xhtml href="header-l0-inc.html"></w3-include-xhtml>
                    

The naming scheme is also compatible with W3C Custom Elements Proposal,
being incooperated within W3C DOM Spec and the W3C HTML Spec.
Also see the WHATWG DOM Spec and the WHATWG HTML Spec

You must not use the custom tag in a self-closing manner, since the spec seemingly only allows build-in types to be void.
We will detect whether the node has children attached as if no end tag has been provided and insert an error message! This has been observed on Firefox when used as self-closing. See error example at bottom of this page.

Remaining question: How can we surpass the W3C Markup Validation Service?

If you see any other text elements besides this text block from Welcome, the custom XHTML element w3-include-xhtml is operating.
In detail, a header HEADER, a sidebar SIDEBAR and a footer FOOTER shall be visible via three w3-include-xhtml elements.

License

This work is licensed under the 'New BSD 2-Clause License'.

---

The faulty example using self-closing:

                        <w3-include-xhtml href="error-self-closing-non-existant-file.html"/>