why my laravel only compute the quantity on the same page and not all the selected item?

selected item before doing the searching

I make an e-commerce like system. the system work fine. but after i use the search bar at the top of the page, and selected the item based on the result of the search, it wont compute the item i selected before i make a search using the search bar.In conclusion, i guess it only counted the selected item if the item are in the same page. here I limit the page length to 200.

result before doing the search

this was successfully computed.

after doing the searching

this is what happen when i use the search bar.

result after doing the search

as you can see, it doent count the previous 2 item.

i will provide the code.

web_item.blade

@extends('frontend.layouts.app')

@section('content')

<link rel="stylesheet" href="{{ asset('css/tablestyle.css') }}" />
<link rel="stylesheet" href="https://cdn.datatables.net/1.11.3/css/jquery.dataTables.min.css">

{!! Form::open(['route' => 'frontend.webitem.confirm', 'method' => 'POST']) !!}

{!! Form::submit('Confirm', ['class' => 'btn btn-primary', 'style' => 'float:right;']) !!}
<br>
<table id="webitem-table" class="table table-bordered">
    <thead>
        <tr>
            <th>Part No</th>
            <th>Description</th>
            <th>Supp Part</th>
            <th>RK Qty</th>
            <th>Dealer Price</th>
            <th>Workshop</th>
            <th>End User Price</th>
            <th>Quantity</th>
            <th>Customer Price</th>
            <th>Part Search</th>
        </tr>
    </thead>
    <tbody>
    </tbody>
</table>

{!! Form::close() !!}

<script>
    $(document).ready(function () {
        $('#webitem-table').DataTable({
            processing: true,
            ajax: '{!! route('frontend.webitem.webitemtable') !!}',
            columns: [
                {data: 'part_no', name: 'part_no', searchable: true},
                {data: 'description', name: 'description', searchable: true},
                {data: 'supp_part', name: 'supp_part'},
                {data: 'rk_qty', name: 'rk_qty'},
                {data: 'dealer_price', name: 'dealer_price'},
                {data: 'workshop', name: 'workshop'},
                {data: 'enduser_price', name: 'enduser_price'},
                {
                    data: 'quantity', 
                    name: 'quantity', 
                    orderable: false, 
                    searchable: false, 
                    render: function (data, type, row) {
                        return '<input type="number" min="0" name="quantity[' + row.id + ']" value="0">';
                    }
                },
                {
    data: 'user_price',
    name: 'user_price',
    orderable: false,
    searchable: false,
    render: function (data, type, row) {
        return '<input type="number" min="0" step="0.01" name="user_price[' + row.id + ']" value="' + data + '';
    }
                },
                {data: 'part_search', name: 'part_search', visible: false, searchable: true}
            ],
            lengthMenu: [100, 200, 500, 1000], // Add this option to show 200, 500, 1000 and All
            pageLength: 100, // Set default page length to 200
            responsive: true, // Enable responsive design
        });
    });
</script>

@endsection

web_confirm.blade

@extends('frontend.layouts.app')




@section('content')
    <div class="container">
        <h1>Selected Items</h1>

        <table class="table table-bordered">
            <thead>
                <tr>
                    <th>Part No</th>
                    <th>Description</th>
                    <th>Supp Part</th>
                    <th>Customer Price</th>
                    <th>Quantity</th>
                    <th>Total Price</th>
                </tr>
            </thead>
            <tbody>
                @foreach ($selectedItems as $selectedItem)
                    <tr>
                        <td>{{ $selectedItem['item']->part_no }}</td>
                        <td>{{ $selectedItem['item']->description }}</td>
                        <td>{{ $selectedItem['item']->supp_part }}</td>
                        <td>{{ $selectedItem['userPrice'] > 0 ? number_format((float) $selectedItem['userPrice'], 2, '.', '') : 'N/A' }}</td>

                        <td>{{ $selectedItem['quantity'] }}</td>
                        <td>{{ number_format((float) $selectedItem['itemTotal'], 2, '.', '') }}</td>
                    </tr>
                @endforeach
            </tbody>
        </table>

        <h2>Total Price: RM {{ $total }}</h2>
        <button type="submit" class="btn btn-primary">Confirm Order</button>
    </div>
@endsection

the is the controller named itemController.php

<?php

namespace App\Http\Controllers\Frontend\webitem;

use Illuminate\Http\Request;
use App\Http\Controllers\Controller;
use App\Models\Access\Webitems;
use App\Models\Access\WebTest;
use Yajra\Datatables\Facades\Datatables;
use App\Models\Order;

class ItemController extends Controller
{
    public function index()
    {
        return view('frontend.webitem.web_item');
    }

    public function webitemtable(Request $request)
    {
        $search = $request->input('search.value'); // Get the search input from DataTables

        $query = Webitems::query();

        // Apply search filters based on 'part_no' and 'description' columns
        if ($search) {
            $query->where('part_no', 'LIKE', "%$search%")
                ->orWhere('description', 'LIKE', "%$search%");
        }

        // Fetch filtered items
        $items = $query->get();

        return Datatables::of($items)
            ->addColumn('checkbox', function ($item) {
                return '<input type="checkbox" data-id="' . $item->id . '" name="selected[]" value="' . $item->id . '" data-group="checkbox-group">';
            })
            ->addColumn('action', function ($item) {
                return '<input type="number" min="0" name="quantity[' . $item->id . ']" value="0">';
            })
            ->addColumn('user_price', function ($item) {
                return '<input type="number" min="0" step="0.01" name="user_price[' . $item->id . ']" value="0">';
            })
            
            ->rawColumns(['checkbox', 'action', 'user_price'])
            ->make(true);
    }

   

    public function confirm(Request $request)
    {
        $selectedItems = [];
        $total = 0;

        $items = Webitems::all();

        foreach ($items as $item) {
            $quantity = $request->input('quantity.' . $item->id, 0);
            $userPrice = $request->input('user_price.' . $item->id, 0);

            if ($quantity > 0) {
                $selectedItems[] = [
                    'item' => $item,
                    'quantity' => $quantity,
                    'userPrice' => $userPrice,
                    'itemTotal' => $userPrice * $quantity,
                ];

                $total += $userPrice * $quantity;
            }
        }

        $total = number_format((float) $total, 2, '.', ''); // format the total to 2 decimal places

        return view('frontend.webitem.web_confirm')->with([
            'selectedItems' => $selectedItems,
            'total' => $total,
            'request' => $request,
        ]);
    }
}

this is the route

      Route::group(['prefix' => 'webitem', 'namespace' => 'webitem', 'middleware' => 'auth'], function () {
        Route::get('index', 'ItemController@index')->name('webitem.index');
        Route::get('webitemtable', 'ItemController@webitemtable')->name('webitem.webitemtable');
        Route::get('index_test', 'ItemController@index_test')->name('webitem.index_test');
        Route::get('getDataTable', 'ItemController@getDataTable')->name('webitem.getDataTable');
        Route::post('confirm', 'ItemController@confirm')->name('webitem.confirm');
        
        
        Route::post('/order/confirm', 'ItemController@confirmOrder')->name('order.confirm');

        Route::post('/order/confirm', 'OrderController@confirmOrder')->name('order.confirm');

        Route::post('/submit-order', 'OrderController@submitOrder')->name('submit.order');
        Route::post('/frontend/webitem/process', 'Frontend\webitem\ItemController@confirm')->name('frontend.webitem.process');

on the routes there might be more than needed because ive tried a few things, so just ignore the extra routes and provide with you suggestion

I think you have to use session to save all the selected items. Because seeing at your code I can say that every time you go to selected items page it will reflect only latest selected items. So you need to implement Session to retain your previous selections.