In a Google chrome extension I am working on, a file is downloaded from a server with an `XMLHttpRequest`. This file contains some binary data which are stored in an `ArrayBuffer` object. In order to provide the possibility to download this file I am using the `createObjectURL` API.

```
function publish(data) {
  if (!window.BlobBuilder && window.WebKitBlobBuilder) {
    window.BlobBuilder = window.WebKitBlobBuilder;
  }
  var builder = new BlobBuilder();
  builder.append(data);
  var blob = builder.getBlob();
  var url = window.webkitURL.createObjectURL(blob);
  $("#output").append($("<a/>").attr({href: url}).append("Download"));

```

}

It is working fine; except that the filename is an opaque UUID like `9a8f6a0f-dd0c-4715-85dc-7379db9ce142`. Is there any way to force this filename to something more user-friendly?