As far as I know, each webpage is created in a two stage process: Parsing and rendering; in parsing, markup (Say HTML) is executed as is, or created by executing a "server-side" programming language such as PHP,

In the rendering, the styles (say CSS), is added upon the parsed structures.

My problem

I don't know where does JavaScript come (usually), in parsing or rendering
_{I would assume after rendering but maybe some of it even before rendering was finished;}

My question

Is JavaScript added and executed in parsing or in rendering?

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:

1. Parsing: markup (Say HTML) is executed as is, or created by executing a "server-side" or "backend" programming language such as PHP.
2. 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.

My problem

I don't know where does JavaScript come (usually), in parsing or rendering
_{I would assume after rendering but maybe some of it even before rendering was finished;}

My question

Is JavaScript added and executed in parsing or in rendering?

Comment to user:Niel that might get deleted:

@Neil I have edited the question to example why I didn't forget anything in asking the question; I just didn't know that JavaScript can be loaded in all three stages of a webpages life cycle: Parsing, rendering and interacting, so it's not just "parsing or rendering" as I assumed originally. Reading from amon's answer and then your comment helped me to understand what I described about JavaScript specifically.

AFAIK, each web page is created in a two stage process: Parsing and rendering. In parsing, markup (Say HTML) is taken as is, or created from a server-side programming language like PHP,

In the rendering, the style (say CSS), is added upon the parsed structures.

Yet I don't know where does JavaScript come, in parsing or rendering:

Is JavaScript added and executed in rendering or parsing?

As far as I know, each webpage is created in a two stage process: Parsing and rendering; in parsing, markup (Say HTML) is executed as is, or created by executing a "server-side" programming language such as PHP,

In the rendering, the styles (say CSS), is added upon the parsed structures.

My problem

I don't know where does JavaScript come (usually), in parsing or rendering
_{I would assume after rendering but maybe some of it even before rendering was finished;}

My question

Is JavaScript added and executed in parsing or in rendering?