You have probably encountered interactive elements on web pages before--moving the mouse to cause a new image to appear, clicking on a button to take a survey, and the dreaded pop-up windows.
The technologies used to add interactivity include JavaScript, Java applets, DHTML and server-side includes. JavaScript is a programming language used to add functionality and features to HTML pages. JavaScript's are embedded in HTML files and run on the browser side. Java applets are programs written in Java that can be included inside an HTML page. Dynamic HTML (DHTML) uses a combination of HTML, a scripting language such as JavaScript and Cascading Style Sheets (CSS) to create interactive pages.
In this module, you will not be writing these programs. Is that a relief? We will be using programs that have already been created or I will provide you with the code that you will need. There may be some minor modifications that you will be instructed to make, but nothing major. Our objective is to learn how to use these different elements in a Web page.