a question about designing with JS !?

Question

Hi ... so I'm learning about Java Script and there is a thing that made me confused ~
so while you can create the style of the web with CSS, there are some attribution and stuff in which you can style your web by that!
I mean like :
<script>
var str = new String("Demo Text");
document.write(str.fontcolor( "blue" ));
alert(str.fontcolor( "blue" ));
</script>
then ~ while making a site , where should i style my web page ?!
and in a real website does the programmer build web's style in css or js ?
it's really confusing to me ... . (i'm a newbie :) )
(hope my quesntion doesn't look confusing )

Answer 1

CSS

use a separate css file

in html, call the css with the link tag.

like this :

https://github.com/gorgorgordon/MySoloLearnCodes