display does not work for option element on IE


style=「display:none」does not work for option element
ハロー
I have a select list and I need a way to set certain option tags invisible.I tried appining style=「display:none」to the option tags but this had hadのeffect.
The reason for this that I am going to use some JavaScript to dynamically enable some selections in the drop down list.
Please see the atached code snippet.
Thanks

<select id="counties" tabindex="1">
 <option value="">Select</option>
 <option style="display:none" value="IE76176089">Carlow</option>
 <option style="display:none" value="IE96268862">Cavan</option>
 <option style="display:none" value="IE55624026">Clare</option>
 <option style="display:none" value="GB55624026">London</option>
 <option style="display:none" value="GB55624026">Surrey</option>
</select>