An XHTML-capable browser is required for this demonstration. Windows Internet Explorer is not such a browser.
document.write is functional in an HTML 4.01 Strict document served with the media type text/html.
document.write is functional in an XHTML 1.0 Strict document served with the media type text/html. However, document.write should not be used because it is non-functional when the document is served using XHTML’s native media type of application/xhtml+xml.
document.write is non-functional in an XHTML 1.0 Strict document served with the media type application/xhtml+xml.