Get radio value without refreshing the page

I want to create a form that will submit feedback (good / average / poor) to the mysql database without loading the page I am on. It works great, except that it doesn't recognize which value I am sending (if it is good, average or bad that was sent).

Here's my form:

<form method="post" id="radio_fb" style="margin-top:-90px;">
    <p>
        <input type="radio" name="radios" id="poor" value="poor" /><label for="poor">Poor</label>
        <input type="radio" name="radios" id="average" value="average" checked="checked" /><label for="average">Average</label>
        <input type="radio" name="radios" id="good" value="good" /><label for="good">Good</label>
        <input type="hidden" name="url" value="<?php echo 'http://'.$_SERVER['HTTP_HOST'].$_SERVER['REQUEST_URI'];?> "/>
        <input type="submit" name="submitter" value="Send" id="submit" />
    </p>
</form>

      

        
        
        
      

    

And here is my jQuery:

jQuery(document).ready(function($) {
    $("#radio_fb").submit(function() {
        cname = this.radios.value;
        curl = this.url.value;
        submitter = this.submitter;

        var data = {
            name: cname,
            url: curl
        };
        $.post("ajax.php", data, function() {
            submitter.value="Sent";
            submitter.disabled=true;            
        });

        return false;

    });
});

      

        
        
        
      

    

And here are the functions that store the value in the database:

<?php
include_once('config.php');

if ($_POST['radios'] == 'good') {
    $url = $_POST['url'];
    $bdd->exec('INSERT INTO feedback(id, url, avis) VALUES ("", "'. $url .'", "Good")');
} else if ($_POST['radios'] == 'average') {
    $url = $_POST['url'];
    $bdd->exec('INSERT INTO feedback(id, url, avis) VALUES ("", "'. $url .'", "Average")');
} else {
    $url = $_POST['url'];
    $bdd->exec('INSERT INTO feedback(id, url, avis) VALUES ("", "'. $url .'", "Poor")');
}

?>

      

        
        
        
      

    

Any idea how to fix this? I've looked at all the answers, but nothing seems to work: my function keeps returning the else statement (or nothing if I remove it).