If you like this kind of thing:
- https://en.wikipedia.org/wiki/HTML_Application
- https://en.wikipedia.org/wiki/Microsoft_Compiled_HTML_Help
- https://en.wikipedia.org/wiki/HTML_Application
- https://en.wikipedia.org/wiki/Microsoft_Compiled_HTML_Help
For example, JS and XHRs are in the spec, but few readers allow them, for very good practical reasons.