The SELECT tags allow users to pick one or more options out of a list of possible values supplied in an input form, where each alternative is represented by an <OPTION> element.
MULTIPLE
this attribute appears when users are allowed to select more than one element from the set of <OPTION> values supplied within a <SELECT> ... </SELECT> tag pair.
<SELECT> ... </SELECT> is legal only within the <FORM> tag.
The following markup can be used within <SELECT> ... </SELECT>
<OPTION>
Use to provide pickable lists of scalar values within HTML forms, which are suitable whenever users need pick only from a predetermined set of possible values for an input field.
Please see the Fill In Forms tutorial for examples.