For example, DNS allows your Web browser to find the IP address of index.truman.edu. The process of finding the IP address from a given host name is called IP address resolution. HTTP is usually run on port 80. That sounds relatively simple, and it is. Most modern operating systems include a Web server, which allows you to serve pages from your own computer.
Server software varies greatly in price and features.
An HTML document is a regular text file containing plain text and special strings of characters called tags. These tags indicate the structure of the document, which can be expressed by browsers in an appropriate way. For example, a browser usually displays a first-level header in a larger font than the paragraph below it. Style choices can be made by each user, and structural information can be communicated in different ways. But a browser for the blind might read the text with added emphasis.