title: multiple select with minimum one selected
body: <p>i have a problem with the select and the multiple attribute: i want to have at least minimum 1 option selected, but dont want to use javascript for it. is this even possible without js? the select box looks like this</p>
  
  <pre><code>&lt;select class="span6 m-wrap" id="search_sites" size="3" multiple="multiple" tabindex="1"&gt;
    &lt;option value="Category 1" selected="selected"&gt;Category 1&lt;/option&gt;
    &lt;option value="Category 2" selected="selected"&gt;Category 2&lt;/option&gt;
    &lt;option value="Category 2" selected="selected"&gt;Category 3&lt;/option&gt;
    &lt;option value="Category 3" selected="selected"&gt;Category 4&lt;/option&gt;
  &lt;/select&gt;
  </code></pre>