Notice the string of characters that starts with HTTP (http://www.fredsco.com). The whole string is called a uniform resource locator (URL). The URL identifies the protocol in use, as well as the name of the server. For instance, HTTP stands for Hypertext Transfer Protocol and is the TCP/IP protocol you use to send the web page content from the web server to the web browser. Next, the stuff after the // lists the name of the server. In Chapter 13, I'll tell you more about names in TCP/IP, but for now, just assume that the name www.fredsco.com identifies the computer where fredsco's web server is running.
The first message that the browser sends includes the HTTP command GET (default). That means that the browser has asked the web server to send the browser that server's default web page, also called that server's home page. When the web developer created the web pages and moved them to the server, one web page was defined as the default. So, the server then looks in its configuration and finds the name of the file that holds its home page. Using HTTP, the server sends the contents of a file called home.html back to the browser.
The file that the web server sent by Conner's web browser is an .HTML file type, meaning that the file contains text that conforms to a specification called Hypertext Markup Language (HTML). HTML was the first language used to describe the contents of a web page. When Conner's browser gets the home.html file, the browser understands HTML, so it can then display the right contents in the browser window. Interestingly, when some people got together to create HTTP originally, most of the web content was HTML, and they were creating a protocol with which to transfer the HTML files. That's why the first word in the H 17TTP acronym is hypertext.
Interestingly, although TCP/IP standardizes HTTP in RFC 2616, TCP/IP does not define anything about HTML. HTML does tell the browser what to put in the browser window, what color to make it, what size, and so on, but it does not define anything about how to send and receive data; therefore, TCP/IP doesn't care much about HTML!
In summary, the browser uses HTTP to ask for particular web pages, and the server uses HTTP to actually transfer the files. Web pages are simply stored in files on the server's disk drive. By transferring the files to the browser's computer, the browser can read the content inside the files and display the contents for the end user.
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