filter data by ID

I want an email filtering function.
this is my url :

https://localhost/quantrictvv1/preview/271.

this is my database:

enter image description here

I want the condition that numbers in the email column matching the id of the above url (which is 271) are allowed to appear, I’m new.
I want a filter function with the condition that email equals url’s id 271, what should I do? I’m new to javascript

View :

<div class="row">
                                                          <div class="col-md-12 mt-4">
                                                             <div class="table-responsive">
                                                                 <table class="table" id="records">
                                                                     <thead>
                                                            
                                                                        <tr>
                                                                    
                                                                         <th>Nhận xét</th>
                                                                           <th>Note</th>
                                                                             <!-- <th>Email</th> -->
                                                                                <th>Action</th>
                                                                                  </tr>
                                                                                 </thead>
                                                                                </table>
                                                                              </div>
                                                                            </div>
                                                                          </div>

Javascript :

<script>
    $(document).on("click", "#add", function(e){
        e.preventDefault();
        var name = $("#name").val();
        var email = $("#email").val();
      
        if (name == "" || email == ""){
            alert("Không được để trống");
        }else{
            $.ajax({
                url:"<?php echo base_url(); ?>insert",
                type: "post",
                dataType: "json",
                data: {
                    name: name,
                    email: email
                },
                success: function(data){
                  if (data.responce == "success") {
                      $('#records').DataTable().destroy();
                    fetch();
                    $('#exampleModal').modal('hide');
                    toastr["success"](data.message);
                  }else{
                    toastr["error"]('Ghi chú không thành công');
                  }
                }
            });
            $("#form")[0].reset();
        }
    });
    //fetch records
    function fetch(){   
      //lấy url xuống
          var check = window.location.href ;
          var final = check.substr(check.lastIndexOf('/') + 1);
           var text = <?= $text_from_db; ?>
        $.ajax({
            url:"<?php echo base_url();?>fetch",
            type: "post",
            dataType: "json",       
            success: function(data){         
                var i = "1";
                var check_id_js = $("#check_id_js").val();         
                $('#records').DataTable({
               "data": data.posts,
               
            columns: [
                {"render": function(){
                    return a = i++;
                }},
                
                { data: 'name',
                 },
                //{ data: 'email' },
                { "render": function ( data, type, row, meta ) {
           var a = `<a href="#" value="${row.id}" id="del" class="btn btn-sm btn-outline-danger"><i class="fas fa-trash"></i></a>
                                        <a href="#" value="${row.id}" id="edit" class="btn btn-sm btn-outline-success"><i class="fas fa-edit"></i></a>`;
                                return a ;
        } }
            ],
        });
            }
        });
    }
       fetch();
      // Delete Record
    
          $(document).on("click", "#del", function(e){
            e.preventDefault();
    
            var del_id = $(this).attr("value");
    
            const swalWithBootstrapButtons = Swal.mixin({
              customClass: {
                confirmButton: 'btn btn-success',
                cancelButton: 'btn btn-danger mr-2'
              },
              buttonsStyling: false
            })
    
            swalWithBootstrapButtons.fire({
              title: 'Are you sure?',
              text: "You won't be able to revert this!",
              icon: 'warning',
              showCancelButton: true,
              confirmButtonText: 'Yes, delete it!',
              cancelButtonText: 'No, cancel!',
              reverseButtons: true
            }).then((result) => {
              if (result.value) {
    
                  $.ajax({
                    url: "<?php echo base_url(); ?>delete",
                    type: "post",
                    dataType: "json",
                    data: {
                      del_id: del_id
                    },
                    success: function(data){
                      if (data.responce == "success") {
                          $('#records').DataTable().destroy();
                          fetch();
                          swalWithBootstrapButtons.fire(
                            'Deleted!',
                            'Your file has been deleted.',
                            'success'
                          );
                      }else{
                          swalWithBootstrapButtons.fire(
                            'Cancelled',
                            'Your imaginary file is safe :)',
                            'error'
                          );
                      }
    
                    }
                  });
    
    
                
              } else if (
                /* Read more about handling dismissals below */
                result.dismiss === Swal.DismissReason.cancel
              ) {
                swalWithBootstrapButtons.fire(
                  'Cancelled',
                  'Your imaginary file is safe :)',
                  'error'
                )
              }
            });
    
          });
    
    
           // Edit Record
    
          $(document).on("click", "#edit", function(e){
            e.preventDefault();
    
            var edit_id = $(this).attr("value");
    
            $.ajax({
              url: "<?php echo base_url(); ?>edit",
              type: "post",
              dataType: "json",
              data: {
                edit_id: edit_id
              },
              success: function(data){
                if (data.responce == "success") {
                    $('#edit_modal').modal('show');
                    $("#edit_record_id").val(data.post.id);
                    $("#edit_name").val(data.post.name);
                    $("#edit_email").val(data.post.email);
                  }else{
                    toastr["error"](data.message);
                  }
              }
            });
    
          });
          
           // Update Record
    
          $(document).on("click", "#update", function(e){
            e.preventDefault();
    
            var edit_record_id = $("#edit_record_id").val();
            var edit_name = $("#edit_name").val();
            var edit_email = $("#edit_email").val();
    
            if (edit_record_id == "" || edit_name == "" || edit_email == "") {
              alert("Both field is required");
            }else{
              $.ajax({
                url: "<?php echo base_url(); ?>update",
                type: "post",
                dataType: "json",
                data: {
                  edit_record_id: edit_record_id,
                  edit_name: edit_name,
                  edit_email: edit_email
                },
                success: function(data){
                  if (data.responce == "success") {
                    $('#records').DataTable().destroy();
                    fetch();
                    $('#edit_modal').modal('hide');
                    toastr["success"](data.message);
                  }else{
                    toastr["error"](data.message);
                  }
                }
              });
    
            }
    
          });
    </script>

Controllers :

<?php
    defined('BASEPATH') OR exit('No direct script access allowed');
    
     class Welcome extends CI_Controller{
       public function __construct()
       {  
          parent::__construct();
          $this->load->helper(array('form', 'url'));
    
            $this->load->library('form_validation');
          $this->load->model('crud_model');
       }
       public function index()
       {
          $this->load->view('preview');
       }
      public function insert()
        {
            if ($this->input->is_ajax_request()) {
                $this->form_validation->set_rules('name', 'Name', 'required');
                $this->form_validation->set_rules('email', 'Email', 'required');
                if ($this->form_validation->run() == FALSE)
              {
                    $data = array('responce' => 'error', 'message' => validation_errors());
                 }
              else 
             {
               $ajax_data = $this->input->post();
                    if ($this->crud_model->insert_entry($ajax_data)) {
                        $data = array('responce' => 'success', 'message' => 'Ghi chú thành công');
                    } else {
                        $data = array('responce' => 'error', 'message' => 'Không thêm được bản ghi');
                    }
                }
    
                echo json_encode($data);
            } else {
                echo "No direct script access allowed";
            }
        }
        public function fetch(){
            if($this->input->is_ajax_request()){
                if($posts = $this->crud_model->get_entries()){
                    $data = array('responce' => 'success','posts' => $posts);
                }else{
                    $data = array('responce' => 'error','massage' => 'Không tìm thấy dữ liệu');
                }
                echo json_encode($data);
            }else{
                echo "không cho phép truy cập data";
            }
        }
        public function delete(){
            if($this->input->is_ajax_request()){
                $del_id = $this->input->post('del_id');
                if($this->crud_model->delete_entry($del_id)){
                    $data = array('responce' => 'success');
                }else{
                    $data = array('responce' => 'error');
                }
                echo json_encode($data);
            }else{
                echo "không cho phép truy cập data";
            }
        }
            public function edit()
        {
            if ($this->input->is_ajax_request()) {
                $edit_id = $this->input->post('edit_id');
    
                if ($post = $this->crud_model->edit_entry($edit_id)) {
                    $data = array('responce' => 'success', 'post' => $post);
                } else {
                    $data = array('responce' => 'error', 'message' => 'failed to fetch record');
                }
                echo json_encode($data);
            } else {
                echo "No direct script access allowed";
            }
        }
        
        public function update(){
            if($this->input->is_ajax_request()){
    
             $this->form_validation->set_rules('edit_name', 'Name', 'required');
                $this->form_validation->set_rules('edit_email', 'Email', 'required');
                if ($this->form_validation->run() == FALSE)
              {
                    $data = array('responce' => 'error', 'message' => validation_errors());
                 }
              else 
             {
                        $data['id'] = $this->input->post('edit_record_id');
                         $data['name'] = $this->input->post('edit_name');
                         $data['email'] = $this->input->post('edit_email');
    
                    if ($this->crud_model->update_entry($data)) {
                        $data = array('responce' => 'success', 'message' => 'Cập nhật thành công');
                    } else {
                        $data = array('responce' => 'error', 'message' => 'Cập nhật không thành công');
                    }
                }
    
                echo json_encode($data);
    
            }else{
                echo "No direct script access allowed";
            }
        }
     } ''
    models :
    `` ` <?php 
    
        class Crud_model extends CI_Model {
    
            public function get_entries()
            {
                    $query = $this->db->get('crud');
                     if (count( $query->result() ) > 0) {
                        return $query->result();
                     }
            }
    
            public function insert_entry($data)
            {
                return $this->db->insert('crud', $data);
            }
    
            public function delete_entry($id){
                return $this->db->delete('crud', array('id' => $id));
            }      
    
            public function edit_entry($id){
                $this->db->select("*");
                $this->db->from("crud");
                $this->db->where("id", $id);
                $query = $this->db->get();
                if (count($query->result()) > 0) {
                    return $query->row();
                }
            }
    
            public function update_entry($data)
            {
                return $this->db->update('crud', $data, array('id' => $data['id']));
            }
            
    
    }