This document provides an introduction to web development technologies including HTML, CSS, JavaScript, and PHP. It explains that HTML is the standard markup language used to structure web pages, CSS is used to style web pages, and JavaScript adds interactivity. It also distinguishes between client-side and server-side technologies, noting that JavaScript, HTML, and CSS are client-side and run in the browser, while server-side languages like PHP run on the web server. The document provides examples of how each technology works and is used to build dynamic web pages.