Duplicate Form using button - php

Question

I'm trying to duplicate 4 input text. For example I want to duplicate 'Produk Simpanan Saham', then only 4 input on 'Produk Simpanan Saham' div will be duplicated. I already tried a few methods using jQuery but it seem doesn't work.
<form action="" method="post" class="form-horizontal">
<br><br>
<div class="form-group">
Upload File :
<input type="file" name="file">
</div>
<div class="saham">
<div class="w3-container w3-black">
<h3>
<center>Produk Simpanan Saham</center>
</h3>
</div>
<label for="kp_produk">Kode Produk :</label>
<input type="text" name="kp_produk" class="form-control">
<br>
<label for="produk_saham">Produk :</label>
<input type="text" name="produk_saham" class="form-control">
<br>
<label for="bunga_saham">Bunga :</label>
<input type="text" name="bunga_saham" class="form-control">
<br>
<label for="ket_saham">Keterangan :</label>
<input type="text" name="ket_saham" class="form-control">
</div>
<div class="harian">
<div class="w3-container w3-black">
<h3>
<center>Produk Simpanan Harian</center>
</h3>
</div>
<label for="kp_harian">Kode Produk :</label>
<input type="text" name="kp_harian" class="form-control">
<br>
<label for="produk_harian">Produk :</label>
<input type="text" name="produk_harian" class="form-control">
<br>
<label for="bunga_harian">Bunga :</label>
<input type="text" name="bunga_harian" class="form-control">
<br>
<label for="ket_harian">Keterangan :</label>
<input type="text" name="ket_harian" class="form-control">
</div>

Answer 1

you mush have blueprint of field first like
var blueprint= '<div class="saham">'+
'<div class="w3-container w3-black">'+
'<h3>'+
'<center>Produk Simpanan Saham</center>'+
'</h3>'+
'</div>'+
'<label for="kp_produk">Kode Produk :</label>'+
'<input type="text" name="kp_produk[]" class="form-control">'+
'<br>'+
......
used [] for all name field to get array request when you send form to server
example :
'<input type="text" name="kp_produk[]" class="form-control">'+
and make button add like (jquery) example
<button onclick="$('form').append(blueprint)">add</button>

Answer 2

just use
var dom=$($('.saham')[0]).clone();
//copy dom
$('.form-horizontal').html(dom):
//paste dom
dont forget to add [] on name tag dom input to set data send to array, because if you not set. data with key kp_produk value is last tag name with name kp_produk
if you use [] (kp_product[]) data will set to array
kp_product=['anu1',anu2];