How HTML, CSS and JavaScript Work Together in Web Pages
http://www.webdesignfromscratch.com/how-html-css-js-work-together.cfm

Hunt, Ben
Web Design From Scratch
2006

Abstract:

The three main technologies used to create modern web pages (HTML, CSS and JavaScript) each do different jobs. HTML should be used only for structuring content. Cascading Style Sheets should be used for applying all visual styles. JavaScript should be used for (almost) all interactive functionality, and should always be referenced in separate files, never written into HTML.