Safari® and WebKit Development for iPhone® OS 3.0

Chapter 2. Working with Core Technologies

Whereas a native iPhone app is built entirely in Objective-C, an iPhone Web app is composed of a variety of core technologies that serve as interlocking building blocks. HTML provides structure for the user interface and application data, and CSS is used for styling and presentation. JavaScript and Ajax provide the programming logic used to power the app. And, depending on the app, it may have a backend application server, such as Java or PHP.

Books on programming native iPhone apps often have a primer chapter on the basics of Objective-C to make sure everyone is speaking the same language, so to speak. And, although an entire book could easily be filled writing a primer on the core Web technologies you will work with to develop an iPhone Web app, I do want to explore some of the key technologies you'll need to be sure you know about to be successful.

So as not to start from ground zero, I will assume that you at least know the basics of HTML and have a working knowledge of CSS. That's why I will spend most of my time talking about both the scripting logic layer and the Document Object Model (DOM). However, before I do so, I want to highlight the new HTML 5 tags that Safari on iPhone supports for embedding media into your Web app.

Exploring HTML 5 Media Elements

Before iPhone OS 3.0, working with video inside of an iPhone Web app usually consisted of a simple link to a YouTube clip, which then launched the YouTube app. Because Safari on iPhone ...