Restrict input if the stock is smaller (article table)?

Good morning, I am starting with the development of an online store, I would like you to guide me. I clarify that I am new to PHP. The code is as follows:

<?php
    $query = "SELECT urlImagen, codigoArticulo, descripcionArticulo, 
    unidadDeVenta, articulo.idArticulo FROM articulo INNER JOIN imagen ON 
    articulo.idArticulo = imagen.idArticulo and imagen.idArticulo = 
    '$idArticulo' ORDER BY articulo.idArticulo ASC LIMIT 1";

   $result = mysqli_query($ConexionBD, $query);
   while($row = mysqli_fetch_array($result)) {                                  
?>

<h4>Cantidad</h4>
<div class="product-more-details">
    <div class="row">
      <div class="col-lg-2">

       <!-- aquí mi duda del input, de cómo será la condición de cuando yo 
            escriba una cantidad mayor que me muestre un mensaje de que el 
            stock es menor
        -->
        <input type="text" name="quantity" id="quantity<?php echo 
            $row["idArticulo"]; ?>" class="form-control" value="1" />


        <input type="hidden" name="hidden_urlImagen" 
          id="urlImagen<?php echo $row["idArticulo"]; ?>"
          value="<?php echo $row["urlImagen"]; ?>" />

        <input type="hidden" name="hidden_codArticulo" 
         id="codArticulo<?php echo $row["idArticulo"]; ?>" 
         value="<?php echo $row["codigoArticulo"]; ?>" />

        <input type="hidden" name="hidden_descrip" 
         id="descrip<?php echo $row["idArticulo"]; ?>" 
        value="<?php echo $row["descripcionArticulo"]; ?>" />

        <input type="hidden" name="hidden_price" id="price<?php echo 
         $row["idArticulo"]; ?>"
         value="<?php echo $row["unidadDeVenta"]; ?>" />
     </div> <!--end class="col-lg-2" -->

    <button type="submit" name="add_to_cart" 
     id="<?php echo $row["idArticulo"]; ?>" 
     class="btn btn-warning add_to_cart" >Añadir al carrito</button>

    <button type="submit" class="btn btn-warning" 
      name="buy_to_cart">Comprar</button>
  </div> <!--end class="row" -->
 </div><!--end product more details-->

    <?php
    } //end while
    ?>