Also online you'll find a PDF with links to each of the more than 400 plugins mentioned in the book. You can find the plugins under the lesson where they were mentioned. Click on a link and you'll be taken to the listing in the WordPress.org Plugin Directory.
Conventions
To help you get the most from the text and keep track of what's happening, we've used a number of conventions throughout the book.
WARNING Boxes like this one hold important, not-to-be-forgotten information that is directly relevant to the surrounding text.
NOTE Notes, tips, hints, tricks, and asides to the current discussion are presented in boxes like this.
PLUGINS
At the end of virtually all the lessons, you'll find a box like this with a list of plugins from the WordPress Plugin Directory related to the topics of that lesson. Commercial plugins are not covered here, with the occasional exception.
REFERENCE Reference References like this one point you to the website at www.wrox .com/go/wp24vids to watch the instructional video that accompanies a given lesson.
As for styles in the text:
● We highlight new terms and important words when we introduce them.
● We show URLs and code within the text like so: persistence.properties.
Errata
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To find the errata page for this book, go to www.wrox.com and locate the title using the Search box or one of the title lists. Then, on the Book Search Results page, click the Errata link. On this page, you can view all errata that has been submitted for this book and posted by Wrox editors.
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Section I
Before You Start
Lesson 1
Thinking Like WordPress
WordPress provides you with the tools to create, organize, and update your website content. Those tools function in specific ways, just as one type of word processing software has its specific buttons for creating, say, lists. But there's a difference between knowing which button to press to create a list and thinking about ways to use lists in your documents. That's what this lesson is about: learning to think like WordPress so that you can build or rebuild your website in an efficient and flexible manner from the start, and to use it in new and useful ways.
The driving principle behind this way of thinking is: Store everything in the smallest possible piece; then assemble as needed. It's the way of the digital world – photographs assembled out of pixels, data stored in database fields, or video recorded in bytes. WordPress operates with this kind of thinking, and you can make better use of its power if you think of your website and its content in this way.
Static Versus Dynamic Web Pages
If you right-click while viewing a page in your web browser, you'll see a tool called View Source, which displays the HTML of the page you're currently viewing. If you try this tool, it appears as though you're viewing a single file, but for most websites today, that's an illusion. In most cases there is no corresponding file sitting on a web server. Instead, the server has combined dozens and dozens of files in a split second to create what you're seeing with View Source.
That was not the case in the early days of the Internet, when most web pages were stored as single HTML files. The fact that no assembly was required to produce the code you see in your browser is why they are called static files. They're easy to create and they load quickly (an important factor at a time when computers and Internet speeds were slow), but they aren't flexible. Suppose you decided to change the logo at the top of each of your website's pages, and it had a new file name. With static files, you would need to manually go in and replace the HTML in every file. Not so bad on a 5-page site, but what if you had 5,000 pages? Yes, there's such a thing as search-and-replace functions in HTML editors, but aside from the fact that methods like that are not user-friendly, they solve only one limitation of static files. Suppose you wanted an entirely different header area depending on what part of your site the visitor is on?
The answer is to break up the structure of web pages in such a way that different files control different parts of the final page. So instead of storing web pages as single files, the server would store a series of files that are then assembled into a single file at the moment the page is requested by someone's browser. It is this assembly process that leads us to refer to these types of web pages as dynamic. Figure 1.1 shows one way to split up a static HTML file.
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