select disable

<select id=ss>
  <option>000</option>
  <option>001</option>
  <option>002</option>
  <option>003</option>
</select>
<input type=button οnclick="ss.disabled=!ss.disabled" value=enable/disable>
<input type=button οnclick="alert(ss.options[ss.selectedIndex].innerText)" value=show_selected>
           

 一段有用的代碼