ajax 搜索加分页

<script src="{{asset('js/jquery-3.4.1.min.js')}}"></script>
<center>
    <h2>展示用户</h2>
    <input type="text" class="sou"><button onclick="fun()">搜索</button>
    <br>
    <a href="/login/add">添加用户</a> | <a href="/login">退出登录</a> | <a href="/role">角色展示</a> | <a href="/login/show">用户展示</a>
    <table border="1">
        <tr>
            <td><button class="quan">全选</button> <button class="noquan">全不选</button></td>
            <td>id</td>
            <td>用户名</td>
            <td>密码</td>
            <td>操作</td>
        </tr>
        <tbody class="tbody1">

        </tbody>

    </table>
    <div class="page">

    </div>
</center>
<script>
    fun(1);
    function fun(page){
        var sou = $(".sou").val();
        $.ajax({
            url:"/loginPage",
            type:"post",
            dataType:"json",
            data:{
                page:page,
                sou:sou
            },
            success:function(res){
                $(".tbody1").html(res['arr']);
                $(".page").html(res['but'])
            }
        })
    }

    $(".quan").click(function(){
        var box = document.getElementsByName('box');
        for (i = 0; i<box.length;i++){
            if (box[i].checked == false) {
                box[i].checked = true;
            }
        } 
    })

    $(".noquan").click(function(){
        var box = document.getElementsByName('box');
        for (i=0;i<box.length;i++){
            if (box[i].checked == true){
                box[i].checked = false;
            }
        }
    })
</script>


//php 代码


    public function loginPage()
    {
        $page = isset($_POST['page'])?$_POST['page'] : 1;//当前页
        $sou = isset($_POST['sou'])?$_POST['sou'] : '';
//        echo $page;die;
        $size = 3;//每页3条
        $res = DB::select("select * from user where username like '%$sou%'");
        $count = count($res);//一共条数
//        echo $count;die;
        $bigpage = ceil($count/$size);//最大页数
        $foll = ($page-1)*$size;//偏移量
        $prev = $page - 1 < 1 ? 1 : $page -1;//上一页
        $next = $page + 1 > $bigpage ? $bigpage : $page + 1;//下一页
        $data = DB::select("select * from user where username like '%$sou%' limit $foll,$size");
        $data = json_decode(json_encode($data),1);
//        echo json_encode($data);die;
        $arr = "";
        foreach($data as $key => $v){
            $arr .= "
                        <tr>
            <td><input type=\"checkbox\" name=\"box\" value=".$v['id']."></td>
            <td>".$v['id']."</td>
            <td>".$v['username']."</td>
            <td>".$v['userpassword']."</td>
            <td></td>
        </tr>
            ";
        }
        $but = "
            <button onclick='fun(1)'>首页</button>
            <button onclick='fun($prev)'>上一页</button>
            <button onclick='fun($next)'>下一页</button>
            <button onclick='fun($bigpage)'>尾页</button>
        ";
        $ser['arr'] = $arr;
        $ser['but'] = $but;
        echo json_encode($ser);
    }