discuz的右侧工具栏 scrolltop 修改

<div id="scrolltop">        <!--{if $_G[fid] && $_G['mod'] == 'viewthread'}-->        <span><a href="forum.php?mod=post&action=reply&fid=$_G[fid]&tid=$_G[tid]&extra=$_GET[extra]&page=$page{if $_GET[from]}&from=$_GET[from]{/if}" onclick="showWindow('reply', this.href)" class="replyfast" title="{lang fastreply}"><b>{lang fastreply}</b></a></span>        <!--{/if}-->        <span hidefocus="true"><a title="{lang scrolltop}" onclick="window.scrollTo('0','0')" class="scrolltopa" ><b>{lang scrolltop}</b></a></span>        <!--{if $_G[fid]}-->        <span>                <!--{if $_G['mod'] == 'viewthread'}-->                <a href="forum.php?mod=forumdisplay&fid=$_G[fid]" hidefocus="true" class="returnlist" title="{lang return_list}"><b>{lang return_list}</b></a>                <!--{else}-->                <a href="forum.php" hidefocus="true" class="returnboard" title="{lang return_forum}"><b>{lang return_forum}</b></a>                <!--{/if}-->        </span>        <!--{/if}--></div><script type="text/javascript">_attachEvent(window, 'scroll', function () { showTopLink(); });checkBlind();</script>