栏目高亮判断
必须放到nav循环里面

{leaf:nav } {leaf:if $on}高亮的css{/leaf:if} {/leaf:nav}

首页判断

{leaf:if $index}我是首页{/leaf:if}

或者

{leaf:if $index}我是首页{else}其他页面{/leaf:if}

会员判断

{leaf:if $user}{leaf.user.username}管理中心{leaf:fun url('user')}{leaf:else}登录/user/?r=account/login 注册/user/?r=account/register {/leaf:if}

表单验证码判断

{leaf:if $form['captcha']}{leaf:fun url('system/api/captcha')}{/leaf:if}

外部链接的判断
内容模型新增外部链接字段:link
如果有外部链接则显示显示外部链接

{leaf:if $list[link]}{leaf.list.link}{leaf:else}{leaf.list.url}{/leaf:if}

列表缩略图的判断（A\B效果一样）

A.如果缩略图不为空

{leaf:if !empty($list[image])} haveImg{/leaf:if}

B.如果有缩略图

{leaf:if $list[image]} haveImg{/leaf:if}

默认变量 $i 判断最后一个

{leaf:if $i==count($data)-1}  {/leaf:if}

新增变量 $j 判断最后一个

{leaf:php $j = 0; }
{leaf:if $j==0}第一个{/leaf:if}
{leaf:if $j==count($sata)-1}最后一个{/leaf:if}
//同理 如果要隔行换色 判断$j 是奇偶数就可以了
{leaf:if $j%2==0}a{/leaf:if}
{leaf:if $j%2!=0}b{/leaf:if}
{leaf:php $j++;}

判断列表无内容

{leaf:if !$data}管理员有点懒，啥都木有！{/leaf:if}