On-the-fly Validation of XML Markup Languages using off-the-shelf Tools

Validation of XML documents is often treated as a major operation, performed only at major transitions in the document's life cycle, after it has been created or when it enters some new stage of processing. Users editing XML documents, on the other hand, would appreciate instantaneous feedback of the correctness of the document each time anything changes. Such on-the-fly validation can be implemented in an XML editor using the current version of Java and freely available XML tools. Our experience is that on-thefly validation can be implemented easily without introducing observable delays even on relatively large documents. To demonstrate this, we have built an experimental XML editor which validates documents on-the-fly after every modification. The editor supports editing of DTDs and validation according to DTDs and according to schemas written in W3C XML Schema and Relax NG. On-the-fly Validation of XML Markup Languages using offthe-shelf Tools Table of