Hi, this is what I have done to have dynamic directory creation for file uploads, using the demo files (html, php, js):

I renamed index.html to index.php, commented out the main.js call at the bottom, and pasted its content into the new renamed index.php, edited the js code so that the "url" option initialization looks like this:

<!--<script src="js/main.js"></script>-->
<script>
$(function () {
    'use strict';

    // Initialize the jQuery File Upload widget:
    $('#fileupload').fileupload({
        // Uncomment the following to send cross-domain cookies:
        //xhrFields: {withCredentials: true},
        url: 'server/php/index.php?historia=<? echo $_GET['historia'];?>' // <<<<<<<<<<<<<
    });

    // Enable iframe cross-domain access via redirect option:
    $('#fileupload').fileupload(
        'option',
        'redirect',
        window.location.href.replace(
            /\/[^\/]*$/,
            '/cors/result.html?%s'
        )
    );

    // Load existing files:
    $.ajax({
        // Uncomment the following to send cross-domain cookies:
        //xhrFields: {withCredentials: true},
        url: $('#fileupload').fileupload('option', 'url'),
        dataType: 'json',
        context: $('#fileupload')[0]
    }).done(function (result) {
        $(this).fileupload('option', 'done')
            .call(this, null, {result: result});
    });

});
</script>

Edited the file server/php/index.php to look like this:

error_reporting(E_ALL | E_STRICT);
$historia = $_REQUEST['historia'] ;
require('UploadHandler.php');
if( $historia != '' ){
  $options = array('historia' => $historia);
  $upload_handler = new UploadHandler($options,true);
}
else{
  $upload_handler = new UploadHandler();
}

Edited the file UploadHandler.php:

added new option 'historia' => '', to the constructor set the option 'user_dirs' => true set the option 'download_via_php' => false

modified the function on line 151, to look like this:

protected function get_user_id() {
    return $this->options['historia'];
}

Modified the funcion on line 186, to look like this:

protected function set_file_delete_properties($file) {
    $file->delete_url = $this->options['script_url']
        .'?historia='.$this->options['historia'].'&file='.rawurlencode($file->name); // <<<<<<<<<<<<<<
    $file->delete_type = $this->options['delete_type'];
    if ($file->delete_type !== 'DELETE') {
        $file->delete_url .= '&_method=DELETE';
    }
    if ($this->options['access_control_allow_credentials']) {
        $file->delete_with_credentials = true;
    }
}

In versions over 6.4.3, the function set_file_delete_properties is set_additional_file_properties, and is in the file 246.

Then call the main file from your browser with the variable historia=your_directory such as: my/demo/index.php?historia=new_dir

and it wil use '/server/php/files/new_dir' for uploads and directory reading...

And it seems to be working nicely and smoothly, list directory contents, uploads perfect and deletes as well.

Thanks for this contribution... good work!