How Web-Pages Work

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How Web pages work

1. A web page is a document which can display text, graphics, audio, video and other elements through a web browser.
   1. Web pages are documents stored on web servers.
   2. Web pages contain instructions on how to display content. The most common instructions are in hypertext markup language (HTML).
2. HTML code is interpreted by a web browser. (a software application designed to retrieve and present content on the Web)
   1. The web browser displays the page by reading the instructions in the web document.
   2. The web browser fetches a Web page from a server by a request. A standard http request includes a page address. For example: http://www.w3.org/standards/about.html Links to an external site.
3. Website – a collection of related webpages with a starting point or home page
   1. Web pages are organized in a directory structure on a web server. The web server runs special software to serve up the content by responding to requests.
   2. The content on the Web is available because the Web is a network of computers all over the world.

• The interconnected devices on the Web use a communication standard known as http (hypertext transfer protocol).

1. An address or Uniform Resource Locator (URL) is the method for locating a document on the Web. The URL typically points to the home page or default page (often index.html) that is located in the root folder of the website.
2. The Domain Naming System (DNS) translates domain names in the URL to IP addresses. Every device on the Internet has an Internet Protocol (IP) address. IP addresses are how devices find each other on a network.
3. The documents within a website are typically hyperlinked and a navigation system (or menu) permits the user to move between pages.

1. Webpage Development Standards
   1. The World Wide Web Consortium (W3C) is an international community that develops open standards.
   2. An open standard is a standard that is publicly available and has various rights to use associated with it, and may also have various properties of how it was designed (e.g. open process).

• The W3C developed the standards for HTML and CSS.

1. The W3C mission is to lead the World Wide Web to its full potential by developing protocols and guidelines that ensure the long-term growth of the Web.
2. The HTML standards are constantly evolving to meet the needs of Web users. (The current standard is HTML5.)
3. The W3C also creates standards for website accessibility, mobile web, etc.

• The W3C has a Web Accessibility Initiative (WAI) which develops strategies, guidelines, and resources to help make the Web accessible to people with disabilities. 

1. File Management is essential in Web pages
   1. Filenames should be short, descriptive and without spaces. Some Web servers do not permit the use of blank spaces in folder and filenames.
   2. Web pages should always be saved into a folder. (Teacher note: Help your students by having them create a folder at the point they save their documents. All files related to the Web page need to be organized into this folder)

• A simple website could be organized in just one folder, but large websites need to be organized in some manner.

1. Large websites typically create folders and subfolders contained within the root
2. Relative links are located relative to the current document because the server knows the location of the current document.
3. A relative link will look like this: (also known as a directory path)
   <a href="/photos/photogallery.html">Home</a>

• An absolute link defines the location of the document in total including the protocol required to get the document, the server to get it from, the directory it is located in and then the name of the document itself.
• An absolute link will look like this:
  • <a href="http://www.navegabem.com/index.html">Home</a>