<select name="province" style="width: 150px;" class="province form-control">

       <option>==请选择省==</option>

       @foreach($province as $item)

             <option value="{{ $item->id }}">{{ $item->name }}</option>

       @endforeach

</select>

<select name="city"  style="width: 150px;" class="city">

       <option value="0">==市==</option>

</select>

<select name="area"  style="width: 150px;" class="area">

      <option value="0">==区/县==</option>

</select>

<script src="https://cdn.bootcss.com/jquery/3.4.1/jquery.js"></script>

<script type="application/javascript">

    $(function () {

        //当省选项值发生变化的时候，发送ajax请求，获取对应的市区信息，并渲染

        $('.province').change(function () {

            var province = $(this).val();

            $.ajax({

                //请求方式

                type : "get",

                //请求的媒体类型

                contentType: "application/json;charset=UTF-8",

                //请求地址

                url : "getcity",

                //数据，json字符串

                data : {

                    "province":province

                },

                //请求成功

                dataType:"json",

                success : function(result) {

                    //console.log(result)

                    if(result.status == 0)

                    {

                        var citys = result.data;

                        var optionstr = "";

                        //渲染city选择框

                        for(var i = 0; i < citys.length; i++)

                        {

                            var city = citys[i];

                            optionstr += "<option value='" + city.id + "'>" + city.name + "</option>";

                        }

                        $('.city').html(optionstr);

                    }

                    else

                    {

                        alert(result.message);

                    }

                },

                //请求失败，包含具体的错误信息

                error : function(e){

                    console.log(e.status);

                    console.log(e.responseText);

                }

            });

        })

    })

    $(function () {

        //当市选项值发生变化的时候，发送ajax请求，获取对应的区信息，并渲染

        $('.city').change(function () {

            var city = $(this).val();

            console.log(city);

            $.ajax({

                //请求方式

                type : "get",

                //请求的媒体类型

                contentType: "application/json;charset=UTF-8",

                //请求地址

                url : "getarea",

                //数据，json字符串

                data : {"city":city},

                //请求成功

                dataType:"json",

                success : function(result) {

                    //console.log(result)

                    if(result.status == 0)

                    {

                        var areas = result.data;

                        console.log(areas);

                        var optionstr = "";

                        //渲染city选择框

                        for(var i = 0; i < areas.length; i++)

                        {

                            var area = areas[i];

                            optionstr += "<option value='" + area.id + "'>" + area.name + "</option>";

                        }

                        $('.area').html(optionstr);

                    }

                    else

                    {

                        alert(result.message);

                    }

                },

                //请求失败，包含具体的错误信息

                error : function(e){

                    console.log(e.status);

                    console.log(e.responseText);

                }

            });

        })

    })

</script>

//添加页面 并获取省的信息

    public function addpaper(){

        $province = DB::table('region')->where('pid',100000)->get();

        return view('addpaper',compact('province'));

    }

    //市三级联动

    public function getCity(Request $request)

    {

        $province = $request['province'];

        $citys = DB::table('region')->where('pid','=',$province)->get()->toArray();

        return json_encode(['status' => 0, 'data' => $citys]);

    }

    //区三级联动

    public function getArea(Request $request)

    {

        $city = $request['city'];

        $area = DB::table('region')->where('pid','=',$city)->get()->toArray();

        return json_encode(['status' => 0, 'data' => $area]);

    }