i use this script to upload an image and send data with Ajax.
    <script type="text/javascript">
    <?php $timestamp = time();?>
    $(function() {
        var formInput = $(":input,:hidden").serialize();
        $('#file_upload').uploadifive({
            'auto'             : false,
            'checkScript'      : 'check-exists.php',
            'formData'         : {
                                   'timestamp' : '<?php echo $timestamp;?>',
                                   'token'     : '<?php echo md5('unique_salt' . $timestamp);?>',
                                   formInput
                                 },
            'queueID'          : 'queue',
            'uploadScript'     : 'uploadifive.php',
            'onUploadComplete' : function(file, data) { console.log(data); }
        });
        $('#start_upload').on('click', function () {
            $('#file_upload').uploadifive('upload');
        });
    });
</script>
The form:
    <form id="upload_document">
    <input id="file_upload" name="file_upload" type="file" multiple>
    <input name="form_userid" id="form_userid" type="hidden" value="<?php echo $_SESSION['userId']; ?>" />                      
    <input type="button" id="start_upload" name="uploadenFormSend" value="Bestand(en) uploaden" class="button-pink">                        
                </form>  
When i send the form, $_POST['formInput'] returns:
form_userid=13647
But i only need the value (13647). What can i do to make this happend?
