It is a stable document and may be used as reference material or cited from another document.
W3C's role in making the Recommendation is to draw attention to the specification and to promote its widespread deployment.
This document specifies a syntax created by subsetting an existing, widely used international text processing standard (Standard Generalized Markup Language, ISO 8886(E) as amended and corrected) for use on the World Wide Web.
It is a product of the XML Core Working Group as part of the XML Activity. As a convenience to readers, it incorporates the changes dictated by the accumulated errata (available at to the Fourth Edition of XML 1.0, dated 16 August 2006.
For the convenience of readers, an XHTML version with color-coded revision indicators is also provided; this version highlights each change due to an erratum published in the errata list for the previous edition, together with a link to the particular erratum in that list.
Most of the errata in the list provide a rationale for the change.
When I started programming, java regular expression were a nightmare for me.Because the only other online tool I could find for testing .NET regular expressions was slow and covered with ads, I decided to write a simple AJAX regular expression tester. Copyright © 2008 The Extensible Markup Language (XML) is a subset of SGML that is completely described in this document.Its goal is to enable generic SGML to be served, received, and processed on the Web in the way that is now possible with HTML.