Exercise Explanations

CSS (Cascading Style Sheets) is certainly a familiar term for you. CSS allows setting formatting options in a centralized document that is referenced from HTML files. If the job is done right, and CSS is used consistently in a website, CSS will allow you to make visual changes to the entire site (or parts of the site) with very little effort, just by editing the CSS file. There are many books and tutorials on CSS, including the free ones you can find at http://www.w3.org/Style/CSS/ and http://www.w3schools.com/css/default.asp. Although the article that invented the name AJAX mentions CSS as one of the AJAX ingredients, technically CSS is not required to build successful dynamic web applications. However, its usage is highly recommended because of the significant benefits it brings.

This exercise demonstrates using CSS, and manipulating HTML elements' styles using the DOM. These are usual tasks you will do when building AJAX applications. In the following exercise, you will draw a nice table, and you will have two buttons named Set Style 1 and Set Style 2. These buttons will change the table's colors and appearance by just switching the current styles.

The complete AJAX and PHP tutorial features even more AJAX PHP code examples.