There are three types of lists in HTML:
- Ordered Lists
These are sometimes called numbered lists, and list items that have a specific numerical order or ranking.
- Unordered Lists
These are sometimes called bulleted lists, because they have small bullet icons in front of the list items. They are for lists that don’t have a required order.
- Definition Lists
These are lists of items that have two parts, a term to be defined and the definition.
Use the <ol< tag (the ending </ol> tag is required), to create a numbered list with numbers starting at 1. The elements are created with the <li> tag (the ending </li> tag is not required in HTML, but required in XHTML). For example:
<ol> <li>Entry 1</li> <li>Entry 2</li> <li>Entry 3</li> </ol>
Use ordered lists anywhere you want to show a specific order for the list items to be followed, or to rank items sequentially. These lists are most often found in instructions and recipes.
Use the <ul> tag (the ending </ul> tag is required) to create a list with bullets instead of numbers. Just like with the ordered list, the elements are created with the <li> tag. For example:
<ul> <li>Entry 1</li> <li>Entry 2</li> <li>Entry 3</li> </ul>
Use unordered lists for any list that doesn’t have to be in a specific order. This is the most common type of list found on a Web page.
Definition lists create a list with two parts to each entry: the name or term to be defined and the definition. This creates lists similar to a dictionary or glossary. There are three tags associated with the definition list:
- <dl> to define the list
- <dt> to define the definition term
- <dd> to define the definition of the term
HTML does not require the closing tag for the <dt> or the <dd>, but it’s a good idea to use them so other parts of your design aren’t confused. And the ending tags are required in XHTML.
Here is how a definition list looks:
<dl> <dt>This is a definition term</dt> <dd>And this is the definition</dd> <dt>term 2</dt> <dd>definition 2</dd> <dt>term 3</dt> <dd>definition 3</dd> </dl>
Use definition lists anywhere you have a list that has two parts to each item. The most common use is with a glossary of terms, but you can also use it for an address book (name is the term and the address is the definition), or an HTML form (field name is the term, input box is the definition), or for any list of name/value pairs.