Select/option elements are used for providing a group of options that can be more easliy contained in the viewport interface than a group of radio buttons or checkboxes. If you need to use more than four or five checkboxes, consider using the select/option elements instead of input type="radio" or type="checkbox".
These two widgets are commonly referred to by many different names:
- select/option box
- combo box
- drop down box
- pop up box
Select/Option Essentials
- all select elements must have two or more option descendants
- all option elements must have unique, descriptive value="" attributes
- options should be coded in the HTML file in alphabetical order
Examine the source code of this document for more details.