I have a select form field that allows you to choose multiple options (as used with the SET data type in mySQL). Here is my form:

Format(s): <select name="format_type" size="3" multiple>
<option value="Compact Disc">Compact Disc
<option value="Cassette">Cassette
<option value="Vinyl">Vinyl</select>
When I submit the form, $format_type will only hold the value of the last item selected. For example, if I select all 3, $format_type will hold "Vinyl" only.

What am I doing wrong here? Is the form correct?