Q:

How to call a codeigniter helper function using JQuery AJAX?

I have a function defined in my helper function in codeigniter that returns the formatted price when val and currency id is passed to it.
if(!function_exists('format_price')){
function format_price($val,$curency_id=NULL){
    $CI =& get_instance();
    $CI->load->model('currency_model');
    if ($curency_id) {
        $Result=$CI->currency_model->getcurrency($curency_id);
        $dec_place=round($Result['decimal_place']);
        $value=number_format((float)$val,$dec_place,'.',',');
        return $Result['symbol_left'].$value ." ".$Result['symbol_right'];
    }
    else{
        $Result=$CI->currency_model->getDefaultCurrency();
        $dec_place=round($Result['decimal_place']);
        $value=number_format((float)$val,$dec_place,'.',',');
        return $Result['symbol_left'].$value ." ".$Result['symbol_right'];
    }
   }
}

What I need is to call this function through ajax in javascript code.
is this possible without a controller, or do I have to make a controller?

A:

You need to make a request via controller, then call that function through that controller, something like:
$("#id").change(function()
{       
 $.ajax({
     type: "POST",
     url: base_url + "controller_name/your_function", 
     data: {val: $("#your_val").val(),currency_id: $("#your_cur").val()},
     dataType: "JSON",  
     cache:false,
     success: 
          function(data){
            $("#your_elem").val(data.price);
      }
});

Then on your controller:
public function yourfunction()
{
   $data = $this->input->post();
   $price = format_price($data['val'],$data['currency_id']);
   echo json_encode(array('price' => $price));
}

