Copyright Goodheart-Willcox Co., Inc. 516 Unit 3 Living Online 2. The web browser transmits that to its WWW program on the host server. 3. The HTTP protocol locates the document specifi ed by the URL and requests its delivery to the host. 4. If necessary, the document is delivered via TCP/IP packets to the host. 5. The host delivers the document to the requesting computer using HTTP. 6. The web browser determines how the document should be formatted and displays it. The web uses the Internet, but it is not the Internet. The Internet is an interconnected network of networks. The Internet includes many functions that are not core to the web, such as e-mail, fi le transfers, and instant messaging, although these functions may be offered through web- based services. The key notions of the web are hyperlinks and uniform resource locators (URLs). Hyperlinks A hyperlink is the data needed to navigate to another resource, often a URL for a website, attached to text or an image in a document, as shown in Figure 13-5. The text or image to which the hyperlink is attached is called hypertext. Clicking the hypertext activates the hyperlink and retrieves the resource specifi ed in the hyperlink. In common usage, the term hyperlink is used to mean hypertext, so one might say “click the hyperlink,” or link, instead of saying “click the hypertext.” However, be aware there is a technical distinction between the two terms. Hyperlinks are one of the foundations of the World Wide Web. Web pages contain hyperlinks to other web pages or Internet resources. However, hyperlinks can also be used within documents. For example, the table of contents in a report may contain hyperlinks to the pages in the document indicated by the page numbers. Uniform Resource Locator A uniform resource locator (URL) is an address that points to a specifi c document or other resource on a computer network. Many people call this a web address, but while all web addresses are URLs, a URL is Living Online 1.2.2 FYI FYI The theoretical foundation of hypertext was developed in the 1960s by Ted Nelson and Andries van Dam at Brown University based on earlier work by others. World Wide Web 1. User enters URL 6. Browser displays content 5. Document is delivered to computer via HTTP 4. Document is delivered to host via TCP/IP 2. Browser transmits to host server 3. HTTP locates document Goodheart-Willcox Publisher Macrovector/Shutterstock.com Figure 13-4. The operation of the web is really just a series of simple steps. GS4