AJAX-based file upload in CodeIgniter 2 - php

Question

I'm having some trouble with CodeIgniter 2.1.4 and uploading files via AJAX.
I currently have a form which submits perfectly, like so (views/load_form):
<!--form created to add member to database -->
<?php echo form_open_multipart('index.php/member_record/add_member'); ?>
<?php echo form_fieldset('Create Membership Record'); ?>
<div class="container">
<form id="memberform" role="form">
<?php echo form_label('First Name', 'fname'); ?>
<?php echo form_input('fname'); ?>
</div>
<!--other such fields omitted for brevity-->
<label>Upload scanned ID Card</label>
<input type="file" name="scIDFile" id="scIDFile" />
<p class="help-block">Select image as either JPEG, GIF, PNG</p>
<input id="submit" type="submit" name="submit" value="Create Record" class="btn btn-success"/>
<!--end of view-->
I have a Controller which handled this well (controllers/member_record):
public member_record extends CI_Controller{
public add_member(){
$config['upload_path'] = './files/';
$config['allowed_types'] = 'gif|jpg|png|pdf';
$config['max_size']= 1024*8;
$config['encrypt_name']=TRUE;
$config['overwrite'] =TRUE;
$this->load->library('upload',$config);
foreach($_FILES as $field => $file){
if($file['error'] == 0){
if($this->upload->do_upload($field)){
/*$image_config=array(
'source_image'=>$data['full_path'],
'new_image'=>$data['file_path'].'/thumbs',
'maintain_ratio'=>true,
'width'=>150,
'height'=>100
);
$this->load->library('image_lib',$image_config);
$this->image_lib->resize();*/
}else{
$errors = $this->upload->display_errors();
}
}
}
}
}
And this was fine. However, due to certain new functionality that I'm adding to my view: I need to convert things to AJAX and pass all these values to the back-end through AJAX. I've been able to submit all of the fields (like first-name, last-name) to the backend via POST, however I'm struggling to enable file uploads!
I've tried using jQuery File Upload plugins, but there aren't very clear directions on how one would use them for CodeIgniter 2 (especially given my current code). If anyone can shed some light on this, I would appreciate it.