how to show tinyUrl in the same page(right under the form) in codeigniter?

Question

I am working on a code-igniter project to integrate tinyurl api. when I click submit the url shows in another page. I want to display the tiny url right under the original url.

The form is---

<form class="actionForm" action="get_tiny_url">
    <div class="form-group">
        <label for="title"><?php _e('Url') ?></label>
        <input type="text" class="form-control" id="original_url" name="original_url">
    </div>
    <button type="submit" class="btn btn-primary">Submit</button>
</form>

to show the form

public function url()
    {
        view('url');
    }

the Api for tinyurl is here---

public function get_tiny_url()
    {
        $original_url = $this->input->get('original_url');
        function get_tiny_url($original_url)
        {
            $api_url = 'tinyurlApi' . $original_url;

            $curl = curl_init();
            $timeout = 10;

            curl_setopt($curl, CURLOPT_CONNECTTIMEOUT, $timeout);
            curl_setopt($curl, CURLOPT_RETURNTRANSFER, true);
            curl_setopt($curl, CURLOPT_URL, $api_url);

            $new_url = curl_exec($curl);
            curl_close($curl);

            return $new_url;
        }

        $tiny_url = get_tiny_url($original_url);

        echo $tiny_url;
    }

Now how do I show the tiny url right under the form?