Fallback for FormData in IE 8/9

FormData does not exist in IE 8/9 but I need that functionality in those browsers. Is there a nice fallback for this?

I would try to send over json data, but I need to pass over a file to the server. I append this file to the formData in modern browsers and just submit an XHR request. Because FormData does not exist in IE 8/9 this obviously fails.

// I cant seem to get this to work with a file.
$.ajax({
    url: '/genericHandlers/UploadDocsFile.ashx',
    type: "POST",
    data: model.toJSON(),
    contentType: 'application/json'
    }).done(function  (data) { 
       log('stuff happened!');
    });

Maybe an alternative is to create a fake form object in js then append the data to that?