新手请教一下怎么把第一项默认打开


我想把第一栏目默认为打开项显示出来
新人不太了解，麻烦各位大大指导一下，谢谢<div id="livechatv3" style="z-index:99;right:0px;" class="lco pngfix">        <div id="lclist" style="display: none; ">
        <div style="width:160px; margin:100px auto auto 38px;">
 
        <div class="bd">
            <dl>
                    <dt class=""><a href="#">第一栏目</a></dt>
 <dd id="first">
<ul>
 <li>栏目2导航</li>
            </ul>
                </dd>
                <dt class=""><a href="#">第二栏目</a></dt>
                <dd class="">
                        <ul>
<li>栏目二导航</li>
                </dd>
            </dl>
        </div>        </div>
    </div><div id="lcfd" class="lco pngfix"></div>
</div></div>
<script type="text/javascript">
$(document).ready(function(){
        var lcleft=$('.topmenu').offset().left+$('.topmenu').outerWidth();
        $("#livechatv3").css({"left":lcleft+"px"});        $('#lclist').find('dt').click(function(){
                if($(this).next('.show').attr('class')==undefined){
                        $('.show').removeClass('show');
                        $('dt.current').removeClass('current');
                        $(this).addClass('current');
                        $(this).next('dd').addClass('show');
 
                }else{
                        $(this).removeClass('current');
                        $(this).next('dd').removeClass('show');                }
                return false;
        });
        
        $('#livechatv3').hover(
                function(){
                        $(this).attr('class','lcc pngfix');
                        $("#livechatv3").css({"left":(lcleft-215)+"px"});
                        $('#lclist').show();
                },
                function(){
                        $(this).attr('class','lco pngfix');
                        $("#livechatv3").css({"left":lcleft+"px"});
                        $('#lclist').hide();

                }
        );

$('#lcfd').toggle(
                function(){
                        $(this).attr('class','lcc pngfix');
                        $("#livechatv3").css({"left":(lcleft-215)+"px"});
                        $('#lclist').show();
                },
                function(){
                        $(this).attr('class','lco pngfix');
                        $("#livechatv3").css({"left":lcleft+"px"});
                        $('#lclist').hide();
                }
        );

        $('#lclist').find('dd').find('li').hover(
                function(){
                        $(this).attr('class','hover');
                },
                function(){
                        $(this).attr('class','');
                }
        );
        
        $('#lclist').find('dt').hover(
                function(){
                        //if($(this).attr('class')==undefined){
                                $(this).addClass('hover');
                        //}
                },
                function(){
                        //if($(this).next('.show').attr('class')==undefined){
                                $(this).removeClass('hover');
                        //}
                }
        );  
});
</script>JS