The application is the browser

except that the browser does not provide enough interface for navigation. only back/forward, and clicking on links.

compare that to an email client or really any other application. hackernews is a messaging application.

a linked CSS file somehow makes the page an application

no, to keep with the analogy, the CSS part IS the application.

XSLT is exactly how current HTML standards allow static client-side includes

well, kind of. you need a lot of code to describe a simple template: https://news.ycombinator.com/item?id=44398626 [1]

and that still doesn't work for cases where you want multiple document in one view though.

it is at least a step in the right direction. it allows me to keep the document separate and free of navigation artifacts (the linked example is not ideal in that case, but it can be done).

but the same is achived if i build an SPA with javascript. the browser first loads the SPA application, and then the application loads the documents to be displayed. that allows me to keep the documents as original on the server. and unlike xslt this also works for multiple documents in the same view.

[1]: for those reading that thread to the end, the chromium issue turns out to be limited to the fedora build of chromium, nightly builds from the chromium website and chrome work.

> except that the browser does not provide enough interface for navigation. only back/forward, and clicking on links.

And that is all that needed. If you want to provide a common structure for navigation, usually a menu, it should be sent as part of the page. Which means the document and the navigation needs to be composed server side (either on the fly, or generated once). Then you can enhance the page client side (which is rarely needed).