a标签的虚线框

<div id="menu">
             <ul>
                 <li id="menuleft"></li>
                 <li id="menucenter">
                     <div><!--直接用ul会出问题-->
                        <ul>
                         <li><a hidefocus="true" href="#">Company</a></li><!--hidefocus对IE有效，css中outline:none对火狐有效-->
                         <li><a hidefocus="true" href="#">Our Store</a></li>
                         <li><a hidefocus="true" href="#">Products</a></li>
                         <li><a hidefocus="true" href="#">Promotion</a></li>
                         <li><a hidefocus="true" href="#">Comtacts</a></li>
                        </ul>
                        <ul>
                         <li id="search">Search</li>
                         <li>
                             <select name="search" style=" margin-top:10px;">
                                 <option>start source</option>
                                </select>
                            </li>
                         <li><img style=" margin-top:10px;" src="images/btnok.gif" /></li>
                        </ul>
                        </div>
                    </li>
                 <li id="menuright"></li>
                </ul>
            </div>