phpcms如何判断是不是首页

{if !$catid}我是首页{/if}

{if !$catid}
    <div class="friendlink">
        <ul>
            <li><h3>友情链接:</h3></li>
            {pc:link  action="type_list" siteid="$siteid" order="listorder DESC" num="10" return="dat"}
            <li><a href="{siteurl($siteid)}/" target="_self" title="{$SEO[&#39;site_title&#39;]}">{$SEO[&#39;site_title&#39;]}</a></li>
            {loop $dat $v}{if $type==0}
                <li><a href="{$v[url]}" target="_blank" title="{$v[name]}">{$v[name]}</a>{else}<a href="{$v[url]}" target="_blank" title="{$v[name]}"><img  src="{$v[logo]}"    style="max-width:90%"  style="max-width:90%" style="border: 0px" alt="phpcms如何判断是不是首页" ></a></li>{/if}
            {/loop}
            {/pc}
            <li><a href=""><strong>申请友链 >></strong></a></li>
        </ul>
    </div>
{/if}