<?php include('include/config.php'); if(!empty($_POST["cat_id"])) { $id=intval($_POST['cat_id']); $query=mysqli_query($con,"SELECT * FROM subcategory WHERE categoryid=$id"); ?> <option value="">Select Subcategory</option> <?php while($row=mysqli_fetch_array($query)) { ?> <option value="<?php echo htmlentities($row['id']); ?>"><?php echo htmlentities($row['subcategory']); ?></option> <?php } } ?>