# Information types in HTML

HTML 4.0 (Strict) provides elements to denote certain types of information. Although there is a default way each element type is presented, it is possible to use style sheets to change the presentation of any element. The types of information that can be represented by HTML elements are:

Headings
  There are six levels of headings in HTML, which should be used to mark page or topic headings in order of their importance.
Lists
  HTML provides two simple list types:
  1. numbered lists (such as this one)
  2. unordered lists.

  It also provides for lists of terms and definitions

About the author
  A special element is provided for contact information about the author of an HTML page.
Definitions
  These can be marked as an inline definition (i.e. defined in a normal paragraph) or in a list of terms and definitions. This list of information types is a definition list itself. It is also possible to use the value `glossary` in the `rel` attribute of a link, if that link is to a definition. In Amaya, the Links and Structure views include any `rel` attributes on links.
Quotations
  These can be marked inline or as blocks. In each case it is possible to mark the source of the quotation using the `cite` element or the `cite` attribute
Sample input, output, computer code
  Elements are provided for samples of `computer code`, variables, `text to be entered` and `sample output`.
Abbreviations and acronyms
  Elements are available to denote abbreviations and acronyms.
Insertions and Deletions
  There are elements to mark text that has been inserted, or should be deleted (This is useful for collaborative editing sub-editing).
Emphasis
  HTML provides two levels of emphasis: ordinary emphasis and strong emphasis.