As far as I know, each webpage is created in a two stage process, initiated by a webserver request and ended in a webserver response:
- Parsing: markup (Say HTML) is executed as is, or created by executing a "server-side" or "backend" programming language such as PHP.
- Rendering: Styles (say CSS), are added upon the parsed structures.
Rendering could be done alongside parsing or after parsing; it depends on who the an web application was built.
I would assume after rendering but maybe some of it even before rendering was finished;
user:Niel that might get deleted: