how can i make multiplication in dinamic row, i just succes make it in the first row, hope fully by image can make you understand what my problem,

and this is my code view

2. <table class="table table-bordered">
3. <tr>
4.    <th><input class='check_all' type='checkbox' onclick="select_all()"/></th>
5.    <th>#</th>
6.    <th>Kode Barang</th>
7.    <th>Nama Barang</th>
8.    <th>Stock</th>
9.    <th>Jumlah</th>
10.    <th>Harga</th>
11.    <th>Total</th>
12. </tr>
13. <tr>
14.     <td><input type='checkbox' class='case'/></td>
15.     <td><span id='snum'>1.</span></td>
16.   <td><input class="form-control" type='text' id='kodebarang_1' name='kodebarang[]'/></td>
17.     <td><input class="form-control" type='text' id='namabarang_1' name='namabarang[]' readonly /></td>
18.     <td><input class="form-control" type='text' id='stock_1' name='stock[]' readonly /></td>
19. <!---all i need is how do i make multiplication auto when user add row-->
20.     <td><input class="form-control" type='text' id='jumlah_1' name='jumlah[]' onkeyup="hitung2();" /> </td>
21. <td><input class="form-control" type='text' id='harga_1' name='harga[]' onkeyup="hitung2();" /> </td>
22.     <td><input class="form-control" type='text' id='total_1' name='total[]'/> </td>
23.   </tr>
24.   </table>
25.   <button type="button" class='btn btn-danger delete'>- Delete</button>
26. <button type="button" class='btn btn-success addmore'>+ Add More</button>
27. <button type="submit" class="btn btn-primary">Submit</button>
28.       

and this is my jquery multiplication

2. function hitung2() {
3. var a = $("#jumlah_1").val();
4. var b = $("#harga_1").val();
5. c = a * b; //a kali b
6. $("#total_1").val(c);
7. }

i think my problem is how to make it in array ? thanks for any respon, Thanks