A question posed in the FileMaker Community asked if there was a way to validate XML. Interestingly, there are solutions for this in javascript that we can use to pass a result back to a FileMaker script. Based on some javascript found online regarding finding unclosed tags in XML, by adjusting the javascript a little bit, we can have it use a FMP URL to call a script in the parent FileMaker File and pass the result back as a script parameter.
Sample Javascript from Stack overflow here: http://stackoverflow.com/questions/25898719/how-to-find-invalid-unclosed-xml-tags-in-a-variable-using-jquery
This referenced a source of w3 schools, but that link no longer seems to work: http://www.w3schools.com/dom/dom_errors.asp
Now updated to support FileMaker 16.
Read more here: http://www.soliantconsulting.com/blog/2017/06/filemaker-16-javascript-changes