AJAX will do it, but there are permission issues. You can't test it from your local host. If you export & upload to your site, and the file is (I'm not sure of the rules) on the site somewhere, you should be able to access it.
I just tried this myself and it worked.<img src="http://blackhornettechnologies.com/Construct2Stuff/AjaxFileReader.png" border="0" />
The site itself was uploaded to a subdirectory of Construct2Stuff, so the data does not have to be within the project itself.