如何在php的select选项中添加复选框？

I make a php page i want to attach check box with list box option value how i attached checkbox,here is my code:

<select name="recepients[]" multiple size="10" multiple="multiple" >
     <?
        //echo $eventid=$_POST['events'];
        $count=count($_POST['events']);
        for($i=0; $i<$count; $i++){
            $select="select b.first_name,b.last_name from buyers b,registrations r where b.buyer_id=r.buyer_id and r.event_id='".$_POST['events'][$i]."' group by r.buyer_id";
            $res = $GLOBALS ['mysqli']->query ($select) or die ($GLOBALS ['mysqli']->error . __LINE__);
            if ($res->num_rows > 0)
            {           
                while($row = $res->fetch_assoc ())
                {
                ?>
                <input type="checkbox" name="receptionts[]" checked="checked"/> 
                <option value="<?=$row['first_name']?>"><?=$row['last_name']?></option>
                <?
                }
            }
        }
        ?>
 </select>

I'm not sure I understand the principle of putting a checkbox in a list.
If this is to select all default item, you may use the lists multipe with the selected option on the option tags

<select multiple size="10">
...
    <option selected="selected" value="<?=$row['first_name']?>"><?=$row['last_name']?></option>
....

good luck :)

Well, you can make a field in your database that contains selected=selected if you want it selected. Then echo $row['selected']