The initial purpose of HTML was to distribute information on the Internet, but the technique is now widely used within companies in their Intranets.

HTML is used to describe documents that may contain text, images, and links to other pages called hyperlinks. The information contained in the document is used by a browser, such as Firefox or Microsoft Internet Explorer, to display the document contents in a possibly complex format.

Hyperlinks provide access to other documents. When the user clicks on a hyperlink, the document it points to is displayed in a new window, or in a frame if the window is divided into frames.

The basic principle of HTML is the use of tags, ranging from simple to complex. An example of a simple tag is the use of <B> to display text in bold:

which gives the following result:

With standard 4.0 compatible navigator versions, the use of formatting tags such as <font> is not recommended. This standard provides for use of styles, either internal to the page or applied in the header (see below). However, these tags are still recognized and enable rapid application of a format when required.

The current recommendation is to replace these tags with <SPAN style :bold> tags combined with </SPAN> tags. However, the evolution of recommended standards, the fact that HTML codes vary as a function of the navigator and the compatibility with previous versions that is required mean that Web site creators have a wide choice for their HTML processing.

Tags are placed between < and >, most often in pairs, as was seen in the above example. The end tag is identical to the start tag, but is preceded by a slash. For certain tags, only the start tag is required, but an unnecessary end tag generally does not cause problems.

Tags can be nested:

which gives the following result:

This text is in bold, now in bold italic, now not in bold but still italic, now normal.