We might as well begin at the beginning. As you probably know, HTML stands for HyperText Markup Language. Strictly speaking, HTML is not a programming language. Instead, it is a way to mark up a text file so that the file may be presented over computer networks using Internet technologies (mainly the HyperText Transfer Protocol or HTTP).
At the start (i.e., in the early days at CERN, where HTML was invented by Tim Berners-Lee), HTML was used mainly to present, format, and link together text. Over time, the capabilities of HTML and web technology have been extended to include graphics objects such as .gif and .jpg files, sound objects such as RealAudio files, scripts such as JavaScript, stylesheets, and so on. These extensions have greatly expanded the range of things we can do using web technology.
Proceed to Tags and Elements.