Home > Articles > Web Development > HTML/CSS

This chapter is from the book

The Web Bestiary

This section contains a lot of acronyms and definitions. Much of the descriptive material is taken from Wikipedia. In a very real sense, Wikipedia represents the current usage and understanding of these terms by the Web community. I've listed them in order of decreasing importance, or their likelihood of ever coming up in casual conversation. This list is by no means complete.

  • HTML (HyperText Markup Language) The predominant markup language for web pages. It provides a means to create structured documents using semantic tags for such things as headings, paragraphs, lists, links, quotes, and other items. It lets you embed images and other media objects and can be used to create interactive forms.
  • CSS (Cascading Style Sheets) The language for describing the presentation (that is, the formatting and layout) of an HTML document. CSS is designed to enable the separation of document content from the details of how it should be presented, including the typography, positioning, colors, and margins. This separation improves content accessibility and provides more flexibility in controlling presentation characteristics.
  • JavaScript An object-oriented scripting language. Although JavaScript has other uses, we are concerned here about client-side JavaScript—the version that runs inside a user's browser and manipulates HTML page elements. JavaScript code can be embedded within the HTML elements of a web page or imported from a separate file. Not all web pages have JavaScript components, and users can turn off their browsers' JavaScript engine if they want to. Robots generally ignore JavaScript code as they examine web pages.
  • HTTP (HyperText Transport Protocol) The set of rules governing how user agents, web browsers, and the like send requests to a web server and how the web server responds to the request. The web server returns a status code and data, or sometimes just the status code, when something goes wrong. The familiar 404 error code is returned when the web server cannot find what you are looking for. There are two primary HTTP request methods. A Get request is typically sent by your browser when you click a link with the intention of going to another web page. A Post request is typically sent when you click a form's submit button, essentially asking that the web server do something with your input.
  • CGI (Common Gateway Interface) A protocol for dynamically generating web pages in response to a get request or form submission. The term is typically used as an adjective to indicate a server-side process, such as CGI script. CGI programs are typically written using a scripting language such as Perl, Ruby, C, vBasic, or Python. Many websites are entirely driven by CGI processes, although the relative number of such sites has probably been declining as newer technologies, such as AJAX and PHP, have become popular.
  • AJAX (Asynchronous JavaScript and XML) The most recent versions of JavaScript and other client-side scripting languages contain features that a developer can use to create web pages that can make independent HTTP requests to the server while the page is loading or anytime thereafter. AJAX is the set of techniques used to create web pages with elements that can be independently updated with new content in response to a user's mouse click or some other event without having to reload the entire page. This is how many widgets work.
  • XML (eXtensible Markup Language) A set of rules for marking up documents that emphasizes generality and global usability. It is widely used to transmit arbitrarily structured data in mixed client/server environments. XML and HTML are compatible members of a family of markup languages called Standard Generalized Markup Language (SGML). HTML is an SGML language with a specific Document Object Model (DOM) focused on describing hypertext documents. The two technologies are combined in the XHTML specification.
  • JSON (JavaScript Object Notation) Although based on JavaScript, JSON is a language-independent system for representing data objects. It is simpler than XML and is often used as an alternative to XML in AJAX applications to transfer data objects between a server and a script running in a user's browser.
  • CMS (Content Management System) An application program or a package of software tools that facilitates the creation of web pages and automates their maintenance using a Web-based interface for authoring, editing, and administration. The term has broader use beyond the Web. For our purposes, it refers to any site or software that generates web pages from content stored in a database and provides a means of creating, editing, and managing that content without requiring knowledge of HTML, CSS, or FTP. A good CMS permits you to directly enter HTML with the content for finer control of web page presentation. Blogs are a form of content management system.
  • Flash (Adobe Flash, formerly Macromedia Flash) A popular multimedia platform for adding animation and interactivity to web pages. Flash is commonly used to create animations, advertisements, and various interactive components, to integrate video into web pages and to develop rich Internet applications. Some websites are done entirely in Flash. However, this is now considered a poor practice, partly because the content of a Flash site is generally inaccessible to robots.
  • PHP (PHP Hypertext Preprocessor) PHP originally stood for Personal Home Page. The PHP Group, the informal organization that currently oversees the development of the language, decided to expand the meaning of PHP a few years ago and gave us the current recursive acronym. PHP is a server-side technology for dynamically generating websites. It is powerful and easy to write but often difficult to read. A PHP file intermixes program logic—PHP statements enclosed in special tags—with HTML markup. When a request is sent to a web server for a file ending with the .php extension, the web server preprocesses the coded file, executes the PHP instructions, and returns an HTML document to the user's browser. Many modern Web applications, such as the popular blogging software WordPress, are written in PHP.
  • FTP (File Transfer Protocol) An Internet protocol for transferring files from one computer to another, usually using a stand-alone application. Web browsers and page editors also use FTP to upload and download files. Dozens of FTP clients are available. One of the most popular is FileZilla, a free, open-source program that runs on Windows, Macintosh, and UNIX computers.
  • jQuery (JavaScript Query Language) A library of JavaScript functions (often called a framework) that simplifies the development of dynamic, interactive web pages. It provides a language for selecting DOM elements and giving them complex behaviors. jQuery takes care of cross-browser differences in the DOM and facilitates the use of AJAX. In much the same way that CSS does with web page presentation, jQuery encourages the separation of semantic HTML markup from the descriptions of how HTML elements should respond to events. jQuery makes Web programming fun.
  • RSS (Real Simple Syndication) An XML protocol for distributing content. Such distributed content from a website is called a feed and provides an alternative means for users to access the content. Users can subscribe to feeds using a number of stand-alone newsreaders or by using the feed-reading facilities incorporated into their browsers and email clients. Feeds from one website can also be embedded into web pages on another site in a syndicated publishing model. RSS is quite popular but evolved in an ad hoc way and is not a recognized standard. A newer feed protocol called Atom is more robust and follows the applicable standards.
  • DNS (Domain Name System) A system for assigning names to computers connected to the Internet or a private network. It translates domain names meaningful to humans into the numerical addresses associated with networking equipment for the purpose of locating these devices worldwide. The Domain Name System can be thought of as the "phone book" for the Internet.
  • DOM (Document Object Model) A dictionary and grammar for interpreting HTML. A DOM describes HTML elements and their attributes and properties and how they are used to create web pages. DOMs are published in a form that can be read by both humans and machines. Every web browser has at least one DOM, and most modern browsers conform to DOMs published by the W3C. Yet there are still some differences in browser behavior arising from coding bugs, DOM misinterpretation, and edge conditions where browser behavior is not fully defined.

    In this book, whenever you encounter the term DOM, it means the W3C's draft specification for HTML5 as interpreted by your favorite browser. Your browser may or may not support this or that new HTML5 element when you experiment with the examples given. The same is true of any particular editing tool or environment you like to use. My aim is to present HTML that works reliably across all modern browsers and is pleasing to all user agents.

InformIT Promotional Mailings & Special Offers

I would like to receive exclusive offers and hear about products from InformIT and its family of brands. I can unsubscribe at any time.


Pearson Education, Inc., 221 River Street, Hoboken, New Jersey 07030, (Pearson) presents this site to provide information about products and services that can be purchased through this site.

This privacy notice provides an overview of our commitment to privacy and describes how we collect, protect, use and share personal information collected through this site. Please note that other Pearson websites and online products and services have their own separate privacy policies.

Collection and Use of Information

To conduct business and deliver products and services, Pearson collects and uses personal information in several ways in connection with this site, including:

Questions and Inquiries

For inquiries and questions, we collect the inquiry or question, together with name, contact details (email address, phone number and mailing address) and any other additional information voluntarily submitted to us through a Contact Us form or an email. We use this information to address the inquiry and respond to the question.

Online Store

For orders and purchases placed through our online store on this site, we collect order details, name, institution name and address (if applicable), email address, phone number, shipping and billing addresses, credit/debit card information, shipping options and any instructions. We use this information to complete transactions, fulfill orders, communicate with individuals placing orders or visiting the online store, and for related purposes.


Pearson may offer opportunities to provide feedback or participate in surveys, including surveys evaluating Pearson products, services or sites. Participation is voluntary. Pearson collects information requested in the survey questions and uses the information to evaluate, support, maintain and improve products, services or sites, develop new products and services, conduct educational research and for other purposes specified in the survey.

Contests and Drawings

Occasionally, we may sponsor a contest or drawing. Participation is optional. Pearson collects name, contact information and other information specified on the entry form for the contest or drawing to conduct the contest or drawing. Pearson may collect additional personal information from the winners of a contest or drawing in order to award the prize and for tax reporting purposes, as required by law.


If you have elected to receive email newsletters or promotional mailings and special offers but want to unsubscribe, simply email information@informit.com.

Service Announcements

On rare occasions it is necessary to send out a strictly service related announcement. For instance, if our service is temporarily suspended for maintenance we might send users an email. Generally, users may not opt-out of these communications, though they can deactivate their account information. However, these communications are not promotional in nature.

Customer Service

We communicate with users on a regular basis to provide requested services and in regard to issues relating to their account we reply via email or phone in accordance with the users' wishes when a user submits their information through our Contact Us form.

Other Collection and Use of Information

Application and System Logs

Pearson automatically collects log data to help ensure the delivery, availability and security of this site. Log data may include technical information about how a user or visitor connected to this site, such as browser type, type of computer/device, operating system, internet service provider and IP address. We use this information for support purposes and to monitor the health of the site, identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents and appropriately scale computing resources.

Web Analytics

Pearson may use third party web trend analytical services, including Google Analytics, to collect visitor information, such as IP addresses, browser types, referring pages, pages visited and time spent on a particular site. While these analytical services collect and report information on an anonymous basis, they may use cookies to gather web trend information. The information gathered may enable Pearson (but not the third party web trend services) to link information with application and system log data. Pearson uses this information for system administration and to identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents, appropriately scale computing resources and otherwise support and deliver this site and its services.

Cookies and Related Technologies

This site uses cookies and similar technologies to personalize content, measure traffic patterns, control security, track use and access of information on this site, and provide interest-based messages and advertising. Users can manage and block the use of cookies through their browser. Disabling or blocking certain cookies may limit the functionality of this site.

Do Not Track

This site currently does not respond to Do Not Track signals.


Pearson uses appropriate physical, administrative and technical security measures to protect personal information from unauthorized access, use and disclosure.


This site is not directed to children under the age of 13.


Pearson may send or direct marketing communications to users, provided that

  • Pearson will not use personal information collected or processed as a K-12 school service provider for the purpose of directed or targeted advertising.
  • Such marketing is consistent with applicable law and Pearson's legal obligations.
  • Pearson will not knowingly direct or send marketing communications to an individual who has expressed a preference not to receive marketing.
  • Where required by applicable law, express or implied consent to marketing exists and has not been withdrawn.

Pearson may provide personal information to a third party service provider on a restricted basis to provide marketing solely on behalf of Pearson or an affiliate or customer for whom Pearson is a service provider. Marketing preferences may be changed at any time.

Correcting/Updating Personal Information

If a user's personally identifiable information changes (such as your postal address or email address), we provide a way to correct or update that user's personal data provided to us. This can be done on the Account page. If a user no longer desires our service and desires to delete his or her account, please contact us at customer-service@informit.com and we will process the deletion of a user's account.


Users can always make an informed choice as to whether they should proceed with certain services offered by InformIT. If you choose to remove yourself from our mailing list(s) simply visit the following page and uncheck any communication you no longer want to receive: www.informit.com/u.aspx.

Sale of Personal Information

Pearson does not rent or sell personal information in exchange for any payment of money.

While Pearson does not sell personal information, as defined in Nevada law, Nevada residents may email a request for no sale of their personal information to NevadaDesignatedRequest@pearson.com.

Supplemental Privacy Statement for California Residents

California residents should read our Supplemental privacy statement for California residents in conjunction with this Privacy Notice. The Supplemental privacy statement for California residents explains Pearson's commitment to comply with California law and applies to personal information of California residents collected in connection with this site and the Services.

Sharing and Disclosure

Pearson may disclose personal information, as follows:

  • As required by law.
  • With the consent of the individual (or their parent, if the individual is a minor)
  • In response to a subpoena, court order or legal process, to the extent permitted or required by law
  • To protect the security and safety of individuals, data, assets and systems, consistent with applicable law
  • In connection the sale, joint venture or other transfer of some or all of its company or assets, subject to the provisions of this Privacy Notice
  • To investigate or address actual or suspected fraud or other illegal activities
  • To exercise its legal rights, including enforcement of the Terms of Use for this site or another contract
  • To affiliated Pearson companies and other companies and organizations who perform work for Pearson and are obligated to protect the privacy of personal information consistent with this Privacy Notice
  • To a school, organization, company or government agency, where Pearson collects or processes the personal information in a school setting or on behalf of such organization, company or government agency.


This web site contains links to other sites. Please be aware that we are not responsible for the privacy practices of such other sites. We encourage our users to be aware when they leave our site and to read the privacy statements of each and every web site that collects Personal Information. This privacy statement applies solely to information collected by this web site.

Requests and Contact

Please contact us about this Privacy Notice or if you have any requests or questions relating to the privacy of your personal information.

Changes to this Privacy Notice

We may revise this Privacy Notice through an updated posting. We will identify the effective date of the revision in the posting. Often, updates are made to provide greater clarity or to comply with changes in regulatory requirements. If the updates involve material changes to the collection, protection, use or disclosure of Personal Information, Pearson will provide notice of the change through a conspicuous notice on this site or other appropriate way. Continued use of the site after the effective date of a posted revision evidences acceptance. Please contact us if you have questions or concerns about the Privacy Notice or any objection to any revisions.

Last Update: November 17, 2020