在jquery mobile中重新调整选择框的大小？

我想缩小jquery mobile中的选择框

这是我的代码：

 <td >
    <select id="nlocation1" name="nlocation1" data-mini ="true" />

    <?php 
        $sql1="select * from apps.xx_fa_location_mob order by description";
        $res= oci_parse($link, $sql1);
         oci_execute($res);

         while ($row = oci_fetch_array($res))
         {
        $str  = $row[2] ;
        $str_id = $row[1];
        echo "<option value = '$str_id' >$str</option>";

        }



?>

            </select></td>

将css应用于.ui选择

.ui-select{width: 50% !important;}

如果要应用于特定的选择框

<td id="myFirstSelect" >
<select id="nlocation1" name="nlocation1" data-mini ="true" />

<td id="myFirstSelect" >
<select id="nlocation1" name="nlocation1" data-mini ="true" />

#myFirstSelect .ui-select{width: 50% !important;}