HTML stands for Hypertext Markup Language. If you ask a technically inclined person, they might tell you that it is a text formatting language used on the World Wide Web. From a layperson's point of view, it is a series of codes used to put information on a "home page" on the Internet. Who is correct? Both.
HTML was created as a use of the Standard Generalized Markup Language (SGML), which is the International Standard (IS0 8879) for text markup. This standard defines document elements such as paragraphs, various levels of headers, etc.. How those elements are displayed (font type, size, colour, etc.) depends on the bowser that is being used to display the document.
Unless you are working very deeply into HTML though, you don't really need to worry about SGML. All you really need to know is that SGML is a standard for markup languages and that HTML works within this standard.
HTML is the format for all documents on VTN. HTML describes the logical structure of the document, not its appearance, and the way the document is displayed depends on the browser you're using. There are two types of browsers available: text based and graphical. Lynx is text based and cannot view graphics. It is the interface most VTN users see when they dial up. Netscape, as one example is graphical. HTML source code should be written so that it looks good on both types of browsers. It is used on VTN because it is the format of most documents used on the World Wide Web. Because HTML only describes the logical structure of the document you can view HTML documents regardless of what browser you use.
<strong>This text is in bold</strong>
The output would look like this: This text is in bold
All that is required to format the text are the codes between the < sign, and the > sign. So <strong> is considered a code, commonly known as a tag. A pair of tags, such as <strong> and </strong> is known as an element. One thing to note is that in paired tags, the indicators for the beginning tag are < and >. The indicators for the ending tag are </ and >.
There are many examples of tags and elements used in HTML. Some tags are used by themselves, such as <p> and some are used as a pair, such as <em> </em>. In Lynx, the HTML source code can be seen by pressing the '\' key.
Also note that what you see is not always what you get. Bold text in Netscape may not be bold in Lynx. A bulleted list in Mosaic might not be the same as one in Netscape even though the codes are the same. All codes are dependent upon how your browser wants to interpret it.
If you have done a bit of web browsing, you'll notice that an HTML document has structure, much like books or any reading material. Just looking at this page will reveal that it contains paragraphs, section headings, and lists. Links to other documents are also important, they are covered later on.