I am having problem getting the post data in the controller when I send the post request via Jquery Ajax, I have checked with firebug and the form post data is being submitted, but in the controller when I do print_r($_POST); it returns an empty array. What could be wrong ?
Here is the relevant code :
FORM HTML
<form id="contact-form" class="form-horizontal subscribe" accept-charset="utf-8" action="<?= base_url ( 'Contact/' ); ?>" method="post">
    <!--Name-->
    <div class="form-group">
        <label class="sr-only" for="name">Name</label>
        <div class="input-group">
            <div class="input-group-addon"><span class="glyphicon glyphicon-user" aria-hidden="true"></span></div>
            <input id="name" type="text" class="form-control validate" name="name" placeholder="Your full name" value="">
        </div>
    </div>
    <!--Email-->
    <div class="form-group">
        <label class="sr-only" for="email">Email</label>
        <div class="input-group">
            <div class="input-group-addon"><span class="glyphicon glyphicon-envelope" aria-hidden="true"></span></div>
            <input id="email" type="text" class="form-control validate" name="email" placeholder="Your email address" value="">
        </div>
    </div>
    <!--Message-->
    <div class="form-group">
        <label class="sr-only" for="message">Message</label>
        <div class="input-group">
            <div class="input-group-addon"><span class="glyphicon glyphicon-envelope" aria-hidden="true"></span></div>
            <textarea id="message" name="message" class="form-control" rows="3" placeholder="Message"></textarea>
        </div>
    </div>
    <!--Submit Button-->
    <div class="form-group text-right">
        <input id="contact_us" type="hidden" name="contact_us" value="Submit" />
        <button type="submit" id="contact_us" class="btn btn-warning" name="contact_us" value="Submit">
            Send  <span class="glyphicon glyphicon-send" aria-hidden="true"></span>
        </button>
    </div>
</form>
JAVASCRIPT
<script>
$( '#contact-form' ).submit ( function ( event ) {
    event.preventDefault (  );
    event.stopPropagation (  );
    var $scriptUrl = $( '#contact-form' ).attr ( 'action' );
    $.ajax ( {
        method : 'POST',
        url : $scriptUrl,
        data    : $( this ).serialize ( ),
        cache : false,
        processData: false,
        contentType: false,
        dataType : 'json',
        success : function ( data, textStatus, jqXHR ) {
            if ( data.success === true ) { alert ('success'); }
            else { alert ('failure'); }
        },
        error : function ( jqXHR, textStatus, errorThrown ) {
            alert (  jqXHR.responseText  );/*This returns the empty array*/
        }
    } );
} );
</script>
Controller (index function) (http://mysite/Contact - Localhost-wamp)
public function index (  )
{
    print_r($_POST);
}


