HTML5 and CSS3 All-in-One For Dummies

Andy Harris

• Publisher: For Dummies
• Year: 2014
• ISBN:
  9781118421390
• Edition: 3
• Topic: Informatica
• Subtopic: Programmazione in HTML

A new edition of a bestseller covers the latest advances in web development!

HTML5 and CSS3 are essential tools for creating dynamic websites and boast updates and enhanced features that can make your websites even more effective and unique. This friendly, all-in-one guide covers everything you need to know about each of these technologies and their latest versions so that you can use them together. Building on the bestselling formats of the first two editions, this new edition teaches you the fundamentals of HTML5 and CSS3, and then presents ways for using them with JavaScript, MySQL, and Ajax to create websites that work.

• Covers using JavaScript, PHP, MySQL, and Ajax in the context of programming dynamic web pages with CSS3 and HTML5
• Includes self-contained minibooks that review HTML, CSS, design and layout, client-side JavaScript, Ajax and server-side, and putting it all together
• Examines new web development advancements including new technologies and changes to the standards
• Features a website that contains supporting materials including code and several valuable programs that are useful for web development

HTML5 and CSS3 All-in-One For Dummies, 3rd Edition serves as the perfect reference for both web development beginners and seasoned professionals looking to learn more about how to get the most out of the powerful combination of HTML5 and CSS3.

Book IV

Client-Side Programming with JavaScript

Visit www.dummies.com/extras/html5css3aio for more on JavaScript Libraries.

Contents at a Glance

Chapter 1: Getting Started with JavaScript

Chapter 2: Talking to the Page

Chapter 3: Decisions and Debugging

Chapter 4: Functions, Arrays, and Objects

Chapter 5: Getting Valid Input

Chapter 6: Drawing on the Canvas

Chapter 7: Animation with the Canvas

Chapter 1

Getting Started with JavaScript

In This Chapter

Adding JavaScript code to your pages

Setting up your environment for JavaScript

Creating variables

Inputting and outputting with modal dialogs

Using concatenation to build text data

Understanding data types

Using string methods and properties

Using conversion functions

Web pages are defined by the HTML code and fleshed out by CSS. But to make them move and breathe, sing, and dance, you need to add a programming language or two. If you thought building web pages was cool, you're going to love what you can do with a little programming. Programming is what makes pages interact with the user. Interactivity is the “new” in “new media” (if you ask me, anyway). Learn to program, and your pages come alive.

Sometimes people are nervous about programming. It seems difficult and mysterious, and only super-geeks do it. That's a bunch of nonsense. Programming is no more difficult than HTML and CSS. It's a natural extension, and you're going to like it.

In this chapter, you discover how to add code to your web pages. You use a language called JavaScript, which is already built into most web browsers. You don't need to buy any special software, compilers, or special tools because you build JavaScript just like HTML and CSS — in an ordinary text editor or a specialty editor such as Aptana.

Working in JavaScript

JavaScript is a programming language first developed by Netscape Communications. It is now standard on nearly every browser. You should know a few things about JavaScript right away:

• It's a real programming language. Don't let anybody tell you otherwise. Sure, JavaScript doesn't have all the same features as a monster, such as C++ or VB.NET, but it still has all the hallmarks of a complete programming language.
• It's not Java. Sun Microsystems developed a language called Java, which is also sometimes used in web programming. Despite the similar names, Java and JavaScript are completely different languages. The original plan was for JavaScript to be a simpler language for controlling more complex Java applets, but that never really panned out.
  

  Don't go telling people you're programming in Java. Java people love to act all superior and condescending when JavaScript programmers make this mistake. If you're not sure, ask a question on my web page. I can help you with either language.
• It's a scripting language. As programming languages go, JavaScript's pretty friendly. It's not quite as strict or wordy as some other languages. It also doesn't require any special steps (such as compilation), so it's pretty easy to use. These things make JavaScript a great first language.

Choosing a JavaScript editor

Even though JavaScript is a programming language, it is still basically text. Because it's normally embedded in a web page, you can work in the same text editor you're using for HTML and CSS. I'm a big fan of Komodo because the same general features you've been enjoying in HTML and CSS are even more important when you're writing code in a more formal programming language:

• Syntax highlighting: Like it does with HTML and CSS, Komodo automatically adjusts code colors to help you see what's going on in your program. As you see in the later sidebar “Concatenation and your editor,” this adjustment can be a big benefit when things get complicated.
• Code completion: When you type the name of an object, Komodo provides you with a list of possible completions. This shortcut can be really helpful because you don't have to memorize all the details of the various functions and commands.
• Pop-up help: As you enter a function that Komodo recognizes, it automatically pops up a help menu explaining what the function does and what parameters could be placed there.

Picking your test browser

In addition to your editor, you should think again about your browser when you're testing JavaScript code. All the major browsers support JavaScript, and the support for JavaScript is relatively similar across the browsers (at least for the stuff in this chapter). However, browsers aren't equal when it comes to testing your code.

Things will go wrong when you write JavaScript code, and the browser is responsible for telling you what went wrong. Chrome is by far the favorite browser for JavaScript programmers today because it has extremely powerful editing tools. The Firebug plug-in adds many of the same features to other browsers, but it's probably best to start with Chrome because everything you need is already built-in. See Chapter 3 of this mini-book for much more on debugging JavaScript code.

Writing Your First JavaScript Program

The foundation of any JavaScript program is a standard web page like the ones featured in the first three minibooks.

To create your first JavaScript program, you need to add JavaScript code to your pages. Figure 1-1 shows the classic first program in any language.

Figure 1-1: A JavaScript...