The sample page (http://djarvis.bitbucket.org/xml/support.xml) is in XML which is an input Quill and many other WYSIWYG editors do not support (nor claim to). Right now Chrome will not even render this page.
<xsl:include href="xsl/chart.xsl"/>
<xsl:include href="xsl/tags.xsl"/>
So you just fixed the issue? What was the problem causing the mis-render? Thanks for starting the project I think the basic premise of using the browser for selection & apply transforms manually is superb idea, possibly the only one that can work consistently in the current messy environment!
<xsl:include href="xsl/chart.xsl"/>
<xsl:include href="xsl/tags.xsl"/>
<xsl:include href="chart.xsl"/>
<xsl:include href="tags.xsl"/>
https://greenbytes.de/tech/tc/xslt/
The nice idea about client-side XSLT is that you can push the files to servers where you don't have server-side access, and still render the page. Once the XSLT is written, it's relatively easy to migrate to a server-side solution. Using a server-based XSL transformer then removes the headaches associated with client-side XSLT engine differences.
As an aside, here's an interesting XSL file:
https://bitbucket.org/djarvis/world-politics/src/master/xml/...
It transforms any simple XML document (i.e., attribute-free) into a similarly DIV-nested HTML document. The result is that all the pages in the following web site use a single transformation combined with corresponding CSS files:
http://djarvis.bitbucket.org/xml/
Most places I've worked that employ XSLT use a different XSLT file for each (differing) XML document.