php嵌套循环分类怎么写---求大神帮帮忙呀！

php

鼠标悬停的时候，自动显示大分类下的小分类。(JS已经写出来了，就是php部分不会嵌套)

<code> <li class="nav-sub" data-tips="sub-school">                    <a href="<%7B:U('Product/products')%7D>" class="tit">销售与支持</a>                    <div class="nav-line poa"></div>                        <dl class="child cf child_pro">                            <dd class="fl">                                <h1><a href="">产品-1</a></h1>                                <h1><a href="">产品-2</a></h1>                            </dd>                            <div class="fr child_dt">                                <div class="child_p">                                    <img  src="__CN__/images/nav_pic.png"    style="max-width:90%"  style="max-width:90%" alt="php嵌套循环分类怎么写---求大神帮帮忙呀！" >                                    <h5 class="cf">                                        <a href="javascript:;" class="fl">G</a>                                        <a href="javascript:;" class="fl">G</a>                                        <a href="javascript:;" class="fl">G</a>                                    </h5>                                </div>                                      <div class="child_p">                                    <img  src="__CN__/images/nav_pic.png"    style="max-width:90%"  style="max-width:90%" alt="php嵌套循环分类怎么写---求大神帮帮忙呀！" >                                    <h5 class="cf">                                        <a href="javascript:;" class="fl">L</a>                                        <a href="javascript:;" class="fl">L</a>                                        <a href="javascript:;" class="fl">L</a>                                    </h5>                                </div>                             </div>                        </dl>                </li></code>