<form id="form1" name="form1" method="post" action="">
  <select name="select">
    <option value="1">aaaaa</option>
    <option value="2" selected="selected">bbbbb</option>
    <option value="3">ccccc</option>
  </select>
</form>

------解决方案--------------------
探讨

HTML code
<form id="form1" name="form1" method="post" action="">
  <select name="select">
    <option value="1">aaaaa</option>
    <option value="2" selected="selected">bbbbb</option>
    <option value="3">ccccc</option>
  </select>
</form>