it’s basically a way to give the browser plain text and have it output richly formatted and even active content that can be clicked on to some end.
HTML mostly relates to directly inputting content onto a page.
CSS is The Skin, Hair and Clothing
Cascading Style Sheets, or CSS.
The typical web developer workflow might be to insert all the various pure content first into an HTML document, then jump over to CSS and begin crafting that content to appear in a more visually pleasing and usable way
JavaScript jumps into this game by taking a more active role in how the page behaves.
HTML5 developers have some new tags to work with that make the basic structure of a web page more logical.