Ajax data not being sent to controller function (CodeIgniter) - ajax

Question

I have an anchor tag and would like its data-id to be sent to a function in the controller which would in turn retrieved data from the database through the model.
However the data is not getting past the controller. The ajax response is showing that the data was sent but controller shows otherwise.
Here is my ajax code:
$(document).on("click",".learn-more",function(){
var sub_item_id = $(this).data("id");
$.ajax({
url:"<?php echo base_url();?>Designs/business_cards",
type:"POST",
data:{sub_item_id:sub_item_id},
success:function(data){
console.log(data);
},
error: function(error){
throw new Error('Did not work');
}
})
});
I had set datatype:"json" but the data was not being sent so I removed the datatype and it worked,the ajax part that is.Or atleast the response showed that data was sent.
My controller code is:
function business_cards(){
$id = $this->input->post('sub_item_id');
$data['quantity'] = $this->subproduct_model->get_quantities($id);
$this->load->view('category/business-cards',$data);
}
My model code is:
public function get_quantities($sub_item_id){
$this->db->select('quantities');
$this->db->where('id',$sub_item_id);
$query = $this->db->get('sub_products');
return $query->result_array();
}
HTML Code which includes the anchor tag
<?php foreach ($results as $object):?>
View Prices
<?php endforeach?>
The data-id is displaying the correct value as per the iteration.
When I check the result array of the model code it is an empty array showing that the $sub_item_id was not passed in the controller. What could be the problem?

Answer 1

I just copied your code and I was able to get the value in the controller.
In your controller function do var_dump($id). Then in your developer tools (F12) check the console. Since you have console.log(data) that var_dump should be in the console. It won't show on the screen.
Some other things to check:
Does your db have records with that ID? Could your db result array be empty because it actually should be?
Are you sure that the data-id actually has a value when you click the tag?

Answer 2

it is not passed to the controller because you forgot to put a parameter inside the function of your controller.
Note: you cannot use input post because you're not using form.
function business_cards($id){ //put a parameter here, serve as container of your passed variable from **ajax**
//$id = $this->input->post('sub_item_id');
$data['quantity'] = $this->subproduct_model->get_quantities($id); //pass the id to your model
$this->load->view('category/business-cards',$data);
}
change your ajax code to this..
$(document).on("click",".learn-more",function(){
var sub_item_id = $(this).data("id");
$.ajax({
url:"<?php echo base_url('Designs/business_cards/"+sub_item_id+"');?>", //pass the id here
type:"POST",
success:function(data){
console.log(data);
},
error: function(error){
throw new Error('Did not work');
}
})
});