HTML内容：
<li><span>一级分类：</span><select name="yjid" class="yjid"><option value="">---所属分类---</option><volist name="list" id="vo"><option value="{$vo['id']}">{$vo['name']}</option></volist></select></li><li><span>二级分类：</span><select name="ejid" class="ejid"><option value="">---所属分类---</option></select></li>
jQuery内容：
<script>$(function(){$('.yjid').change(function(){var yjid = $('.yjid').val();$.ajax({url:"{:U('index/daohang_add_ajax')}",type:"POST",async:true,dataType:"json",data:{'yjid':yjid},success:function(data){var str = "";$.each(data, function(index, value){str += '<option value="' + value.subid + '">' + value.subname + '</option>';});//清空之前其他上级菜单遗留的子菜单，否则改变上级菜单后子菜单会包含多个上级菜单的全部子菜单$('.ejid').empty(); $('.ejid').append('<option value="">---所属分类---</option>' + str);},});});});</script>
thinkphp内容：
//显示一级分类public function daohang_add(){if(!session('username')){$this->redirect('login/login');}$list = M('type')->select();$this->assign('list', $list);$this->display();}//显示对应二级分类public function daohang_add_ajax(){if(!session('username')){$this->redirect('login/login');}$data = I('yjid');$list = M('sub_type')->where('typeid='.$data)->select();$this->ajaxReturn($list, 'json');}
