<script>
function MM_jumpMenu(targ,selObj,restore){ //v3.0
  window.open(selObj.options[selObj.selectedIndex].value,'','');
  if (restore) selObj.selectedIndex=0;
}
</script>
<select name=menu1 class=tex 
     onChange="MM_jumpMenu('parent',this,0)">      <option value="index.htm" selected>主頁</option>
      <option value="http://.../hrd">工程課</option>
    </select>
是不是这样