getsimple ckeditor upload handler

configfragment.js

// add to config.js editorconfig section. you can add ?path= query to this to use a subfolder
config.imageUploadUrl = "../admin/upload.php"

// add to config.js
CKEDITOR.on( 'instanceReady', function( ev ) {
	// code for fileupload and response
	ev.editor.on( 'fileUploadRequest', function( evt ) {
		var fileLoader = evt.data.fileLoader,
		formData = new FormData(),
		xhr = fileLoader.xhr;
		xhr.open( 'POST', fileLoader.uploadUrl, true );
		formData.append( 'file[]', fileLoader.file, fileLoader.fileName );
		fileLoader.xhr.send( formData );
		// Prevent default behavior.
		evt.cancel();
	}, null, null, 4 ); // Listener with priority 4 will be executed before priority 5.

	ev.editor.on( 'fileUploadResponse', function( evt ) {
			// Prevent the default response handler.
			evt.stop();
			// Get XHR and response.
			var data = evt.data,
			xhr = data.fileLoader.xhr,
			response = xhr.responseText;
			if ($(response).find('div.updated').html()) {
				resphtml = $(response).find('div.updated').html();
				url = $("a",resphtml).attr("href");
				data.url = url;
				$('div.bodycontent').before('<div class="updated"><p>' + resphtml + '</p></div>');
				return;
			}

			if ($(response).find('div.error').html()) {
				resphtml = $(response).find('div.error').html();
				msg = resphtml;
				data.message = msg;
				$('div.bodycontent').before('<div class="error"><p>' + resphtml + '</p></div>');
				evt.cancel();
				return;
			}
	} );
}); 

not sure i understand