input[];

For the full example:
    <form>
       <select NAME="input[]" SIZE=3 MULTIPLE>
          <option VALUE="opt1">option1
          <option VALUE="opt2">option2
          <option SELECTED VALUE="opt3">option3
       </select>
    </form>
 

##</code><code>##


a.
<select name="myname" multiple>

b.
<select name="myname[]" multiple>