A more viable solution for my situation is to set the NetWebPage to HTML, allow it to send the server header text rows, then inject my StringTheory object and return before the template code generates all the HTML, HEAD, TITLE and other tags and code.
While I could just mark the checkboxes not to include scripts, css, etc, I'd still prefer not to inject the various duplicate sections into the middle of my page... even though the various browsers seem to handle it OK.
In any event, with the server headers sent, Chrome stops complaining and lets my <div> refresh work even if the server is set to a non-standard port.
Another reminder to test weird stuff on all browsers, since IE, Edge, and Firefox worked with my original kludge.
Jane