I've made a very simple fiddle here, and you can check it out in different browsers.
It only works in Firefox. In other words, seems that $('#select-tag-id option:visible')
doesn't work in other browsers. What's wrong? Is it a jQuery bug?
The code is:
<select id='items'>
<option value='1' style='display: none;'>One</option>
<option value='1' style='display: block;'>Two</option>
<option value='1' style='display: block;'>Three</option>
<option value='1' style='display: none;'>Four</option>
</select>
and the JavaScript (jQuery code) is:
$(function(){
alert($('#items option:visible').length);
});