Users connect to the Internet through a variety of methods. A relatively inexpensive but slow way to connect is with dialup service, which involves using a modem and a phone line. Faster ways to connect include DSL (digital subscriber line), cable modem, satellite, and ISDN (integrated services digital network). Networks include special wireless transmitters that allow computers to access the Internet wirelessly. Companies that help you connect to the Internet are known as Internet service providers, or ISPs.

Connection speeds play an important part in a user's Internet experience because slower connections result in slower file transfers and Web page viewing. Dialup connections offer the slowest access to the Internet at up to 56 kilobits per second, or Kbps, followed by ISDN connections at 64 to 128 Kbps. DSL usually offers connection speeds of up to 3 megabits per second, or Mbps, while cable modems can achieve speeds of up to 6 Mbps. A Web page that takes about 20 seconds to download via dialup can take less than a second using a cable modem.

Communication Standards

The Internet infrastructure relies on a variety of protocols that dictate how computers and networks talk to each other. For example, Transmission Control Protocol/Internet Protocol, or TCP/IP, is a set of rules that control how Internet messages flow between computers. HyperText Transfer Protocol, or HTTP, is a set of rules that determine how browsers should request Web pages and how server computers should deliver them. Having agreed-upon protocols allows seamless communication among the many different types of computers that connect to the Internet.

The World Wide Web

The World Wide Web is a giant collection of documents, or pages, stored on computers around the globe. Commonly called the Web, this collection of pages represents a wealth of text, images, audio, and video available to anyone with a computer and an Internet connection. Web pages are stored on servers, which are Internet-connected computers running software that allows them to serve up information to other computers. When you place a text file, image, or other document in a special Web directory on a server, that information is available for other Web users to view. Chapter 15 talks about how to transfer information to a Web server.

URLs and Links

Every page on the Web has a unique address called a URL, which is short for Uniform Resource Locator. A URL looks like this:

http://www.example.com/index.html

If you know a page's URL, you can type it into a Web browser to view that page over the Internet. You can also view pages by way of hyperlinks, or simply links, which are clickable words or images on Web pages. Every link on a Web page is associated with a URL that leads to another page on the Internet. Users can jump from one Web page to another by clicking links. Chapter 6 discusses how to create links with HTML.

Browsers

A Web browser is software that allows you to view and interact with Web pages. When you type a URL or click a link in a Web browser, the browser retrieves the appropriate page from a server on the Internet and displays that page. Microsoft Internet Explorer, Mozilla Firefox, and Apple Safari are the three most popular browsers in use today. Each program has evolved through a number of versions, with newer versions supporting more recent Web features. As you build your pages using HTML code, remember that different browsers may display your pages slightly differently depending on the version.

HTML consists of text interspersed with special instructions known as tags. Surrounded by brackets, < >, HTML tags tell a browser how to organize and present text, images, and other Web page content. Many tags are written using an opening tag and a closing tag that surround content that appears on the page. When writing HTML tags, you can use upper- or lowercase letters. To make the coding easy to distinguish from other text in the page, you can type tag names in uppercase. For details, see the section "Understanding HTML Syntax."

When a browser displays a Web page, it retrieves the HTML file for that page from a server, parses the HTML tags to determine how the content should be formatted, and renders the page. The HTML tags tell the browser what images, video, audio, and other content need to be downloaded and integrated into the page. The HTML may also tell the browser to download style sheets and interactive scripts to further enhance the page. To view the HTML underlying a Web page, see the section "View HTML Code in a Browser."

HTML Standards

The World Wide Web Consortium, or W3C, is the primary group guiding the evolution of the HTML language. The W3C is made up of hundreds of companies and organizations including Web industry leaders such as Microsoft, Apple, and Google. The standards developed by the W3C give developers of Web servers and browsers a set of common guidelines with which to develop their products. You can visit the W3C's Web site at www.w3.org.

HTML Versions

The most recent version of HTML is 4.01. Version 4.01 includes rules for using more than 90 HTML tags, most of which are covered in this book. It improves on previous versions by adding better support for multimedia, scripting, and style sheets. Support for style sheets is especially important because it allows developers to apply more precise formatting to Web pages. It also allows developers to keep complex styling information separate from the rest of the HTML. Style sheets are covered in Chapters 10, 11, and 12.

XHTML

XHTML, or Extensible HyperText Markup Language, is an alternative language for coding Web pages that conforms to the stricter standards of XML, or Extensible Markup Language. XHTML is tag-based and uses many of the same tags as in HTML. However, in XHTML, all tags must be closed, tag names and attributes must be coded in lowercase, and attribute values for tags must be surrounded by quotes. Most modern browsers can read both HTML and XHTML. Although XHTML is not covered in this book, you can read more about it at the W3C site at www.w3.org.

Next Generation of HTML

As this book is being published, the W3C is developing the specification for HTML 5, the next version of HTML. This version will introduce features to help Web designers more easily create and maintain the dynamic pages seen in many of today's Web sites. HTML 5 will include tags for defining headers, footers, and navigation sections, along with tags for adding interactive elements such as editable and sortable tables. For more information, see www.whatwg.org/html5.

Most computer operating systems come with a Web browser already installed. Microsoft Windows Vista computers include the Internet Explorer browser, while Apple Mac computers include the Safari browser. (The examples in this book use Internet Explorer.) Mozilla Firefox is another Web browser that has become increasingly popular in recent years. You can learn more about Firefox and download it free at www.mozilla.com/firefox. For more information about the Web browsers in use today, see the Wikipedia at http://wikipedia.org/wiki/Web_browser.

There are many Web browsers in use today, and numerous versions of each. While most of them interpret HTML essentially the same way, slight differences in interpretation mean that not all of them display Web pages exactly the same way. Also, some more recent browser versions recognize newer HTML features that older browsers do not. You can avoid surprises by writing clean, well-formed HTML code and testing your pages in different browsers as you work. The Wikipedia offers a detailed comparison of Web browser features at http://wikipedia.org/wiki/Comparison_of_web_browsers.

Simple text editors, also called plain-text editors, are easy to find. Microsoft Windows Vista comes with Notepad, while Apple Mac computers come with TextEdit. Simple text editors offer no-frills word processing and are often the best choice when you are learning to write HTML. This book uses the Windows WordPad and Notepad text editors in its examples. The Wikipedia has a list of free and commercial text editors at http://wikipedia.org/wiki/ List_of_text_editors.

HTML editors, such as Adobe Dreamweaver and Microsoft Expression, are dedicated programs for writing HTML code and managing Web pages. These programs can shield you from having to write HTML code by offering a graphical environment for building Web pages as well as a text-based environment. Most HTML editors will also color your HTML tags for easier viewing, validate your code, and help you upload finished pages to a server.

You can also use word processing programs, such as Microsoft Word, to write HTML. In Word, you can select HTML as the file type when you save a document, and the program automatically adds the appropriate HTML tags. However, commercial word processors tend to store lots of extra information with your HTML, which can make it a challenge to edit the files in other editors.

In HTML, tags determine how page content is organized and formatted. Tags consist of words or abbreviations surrounded by angle brackets, < >. Tags can be written using upper- or lowercase letters. You can type tag names in uppercase to distinguish the code from other text. This HTML code creates a paragraph in your page:

<P>Hello, world!</P>

Certain structural HTML tags identify different parts of your HTML document. For example, the <BODY> and </BODY> tags surround the main body content that appears in the browser window. Many tags, such as the paragraph tags (<P> and </P>), are written using an opening tag and a closing tag while others, such as the image tag (<IMG>), stand alone. Closing tags must always include a slash (/) before the tag name.

It is important to understand the audience that will visit the pages on your Web site. It is important to know their technical ability so that you can use language they are comfortable with. It is also important to know their interests so that you can present imagery and other content that will keep them interested and at your site. You can conduct interviews with potential users early on to get ideas for your site designs. You can also have users test out your site after it launches to get feedback on how to improve it.

The home page is usually the first page a visitor sees when visiting a Web site, so it is important that it concisely communicate the site's purpose and what information users can expect to find. It should also include prominent links to the other important pages on your site. Optimally, users should be able to see all of this information without having to scroll in their browser window. Clear communication is important on all of your site's pages, but especially on the home page.

Site Map

A useful tool for planning your site's overall structure is a site map, which represents your Web pages as boxes and the hyperlinks as arrows. The home page of a site is usually placed at the top of a site map. A site map gives you an overview of the pages you need to build and also shows the navigational structure. You should arrange your pages so that important content is easy to get to from the home page. You can sketch your site map using pencil and paper or using software such as Microsoft Visio, which has tools specifically made for creating site maps.

Linear Structure

A linear site layout moves the user through your content in a step-by-step fashion, like pages in a book. Linear layouts are good for presenting sequential instructions or a narrative story. In a linear layout, each Web page usually links to the next page and the previous page. The site map of a linear site will have the pages arranged one after the other in a line.

Hierarchical Structure

A hierarchical layout resembles a pyramid, with the home page at the top and other pages fanning out from there. A hierarchical site map looks like a company's organizational chart or a family tree. Hierarchical layouts are appropriate for sites with categorized content, such as online merchants. Each branch in such a site represents a product category with the for-sale items at the end of the branches.

Gathering Content

After you plan the pages and structure of your site, you need to gather the content. For simple sites, this may involve writing text and shooting digital photos. More complex sites may require recording audio and video, creating illustrations, and programming interactive media. You can organize all of this content into your Web pages using HTML.