二级分类

前端html

<select name="pid" id="pid">
	<option value ="">一级分类</option>
		{foreach $sql as $vo}
			<option value ="{$vo.id}">{$vo.name}</option>
		{/foreach}
</select>
<select name="class" id="class1">
	<option value ="1">二级分类</option>
</select>

js

$(function(){
	$("#pid").change(function(){
		var  pid=$('#pid').val();
		$("#class1").empty();        //清除原有的值 不然会一直重复
		$.ajax({
			async:true,
		    type:"post",
		    url:"{:url('Shop/ceshi')}",
		    data:{spid:pid},
		    dataType:"json",
		    success:function(data){
			console.log(data);
			var i;
			for (i = 0; i < data.length; i++) {
				$("#class1").append("<option value='"+data[i].pid+"'>"+data[i].name+"</option>");
			}
		    }
		});
	});
})

后台控制器

public function index()
	{
		$db = db('sorts')->where('pid',1)->select();	//一级
		// dump($db);exit;
		$id = input('spid');
		$time = db('sorts')->where('pid',$id)->select();	//二级
		// dump($time);exit;
		$this->assign('sql',$db);	//一级
		$this->assign('sqll',$time);	//二级
		return view('Shop/index');
	}
	public function ceshi()
	{
		$id = input('spid');
		$time = db('sorts')->where('pid',$id)->select();
		return $time;
	}

数据表

效果图