I have made a modal on my website that collects 5 data from a modal form, but when I click the button to perform the action and redirect me to the page where I work with the data that was set, they tell me that they are undefined , they have not been saved, here I show the error: Code:
<div class="modal fade" id="editar-<?php echo $customer['id'];?>" tabindex="-1" role="dialog" aria-labelledby="exampleModalLabel" aria-hidden="true">
<div class="modal-dialog" role="document">
<div class="modal-content">
<div class="modal-header">
<h5 class="modal-title" id="exampleModalLabel">Actualizar producto</h5>
<button type="button" class="close" data-dismiss="modal" aria-label="Close">
<span aria-hidden="true">×</span>
</button>
</div>
<div class="modal-body">
<form id="form" action="logic/actualizarcolumna.php?editar=<?php echo $customer['id'];?>" method="POST">
<div class="form-group">
<label for="recipient-name" class="col-form-label"><b>Nombre del producto</b></label>
<input type="text" name="nombreproducto1" class="form-control" id="nombreproducto1">
</div>
<div class="form-group">
<label for="Precio de compra" class="col-form-label"><b>Precio de compra</b></label>
<input type="text" name="preciocompra1" class="form-control" id="preciocompra1">
</div>
<div class="form-group">
<label for="asddsa" class="col-form-label"><b>Precio de venta</b></label>
<input type="text" name="precioventa1" class="form-control" id="precioventa1">
</div>
<div class="form-group">
<label for="address"><b>Link del producto <a href="https://tinyurl.com/" target="_blank">(Acortar link)</a></b></label>
<textarea name="linkproducto1" placeholder="Link del producto" class="form-control" id="linkproducto1"></textarea>
</div>
<div class="form-group">
<label for="seccion" class="col-form-label"><b>Sección del producto</b></label>
<input type="text" name="seccionproducto1" class="form-control" id="seccionproducto1">
</div>
</div>
<div class="modal-footer">
<button type="button" class="btn btn-secondary" data-dismiss="modal">Cerrar</button>
<a href="logic/actualizarcolumna.php?editar=<?php echo $customer['id'];?>">
<button type="button" class="btn btn-primary">Guardar cambios</button>
</a>
</form>
</div>
</div>
</div>
</div>
PICTURES: