PHP 5/MySQL Programming- P6:computer programming has often been seen as a difficult and arcane skill. Programming languages are difficult and complicated, out of the typical person’s reach. However, the advent of the World Wide Web has changed that to some extent. It’s reasonably easy to build and post a Web page for the entire world to see. The language of the Web is reasonably simple, and numerous applications are available to assist in the preparation of static pages | 3 You should begin by reviewing your HTML skills. Soon enough you re going to be writing programs that write Web pages so you need to be very secure with your HTML coding. If you usually write all your Web pages with a plain text editor you should be fine. If you tend to rely on higher-end tools like Microsoft FrontPage or Macromedia Dreamweaver you should put those tools aside for a while and make sure you can write solid HTML by hand. You should know how to build standard Web pages using modern standards HTML or XHTML including form elements and cascading style sheets CSS . If you need a refresher please see Appendix A which is stored on the CD that accompanies this book. Programming on the Web Server The Internet is all about various computers communicating with each other. The prevailing model of the Internet is the notion of clients and servers. You can understand this better by imagining a drive-through restaurant. As you drive to the little speaker a barely intelligible voice asks for your order. You ask for your cholestoburger supreme and the teenager packages your food. You drive up exchange money for the meal and drive away. Meanwhile the teenager waits for another customer to appear. The Internet works much like this model. Large permanent computers called Web servers host Web pages and other information. They are much like the drive-through restaurant. Users drive up to the Web server using a Web browser. The data is exchanged and the user can read the information on the Web browser. What s interesting about this model is the interaction doesn t have to stop there. Since the client user s machine is a computer it can be given instructions. Commonly the JavaScript language stores special instructions in a Web page. These instructions like the HTML code itself don t mean anything on the server. Once the page gets to the client machine the browser interprets the HTML code and any other JavaScript instructions. While much of the work is passed to the .
