代码1

$form->select('department_id')->options(\App\Models\Department::pluck('name', 'id'))->required()->rules([$unique_rule]);
$form->text('department_nums')->required()->rules([$unique_rule]);

代码2

public function getHeadcount(Request $request)
{
    $id = $request->input('id');

    $department = Department::find($id);

    if (!$department) {
        return response()->json([
            'code' => 1,
            'msg' => 'department does not exit',
        ]);
    }
    return response()->json([
        'code' => 0,
        'data' => [
            'headcount' => $department->headcount,
        ],
    ]);
}

代码3

<script>
        $('#department_id').on('change',function(e){
            $.ajax({
                method: "get",
                url: "/get_headcount?id="+e.target.value,
                success: function (data) {
                    if (data.code === 0) {
                        $('#department_nums').val(data.data.headcount);
                    } else {
                        alert(data.msg);
                    }
                },
                error: function () {
                    alert('获取部门人数失败');
                }
            });
        });
    </script>

要监听选择表单select(‘department_id’)，动态获取department的headcount字段值，回填到text(‘department_nums’)，但不成功，尝试过调整script代码的位置，也修改成下面这种

$form->script = <<<EOT
            $('#department_id').on('change',function(e){
                $.ajax({
                    method: "get",
                    url: "/get_headcount?id="+e.target.value,
                    success: function (data) {
                        if (data.code === 0) {
                            $('#department_nums').val(data.data.headcount);
                        } else {
                            alert(data.msg);
                        }
                    },
                    error: function () {
                        alert('获取部门信息失败');
                    }
                });
            });
            EOT;

但都不成功。本人菜鸟，请高手指点一下，该如何修改代码。测试直接执行get_headcount?id=11是能正常获取到数据的。