Hi, I am working on Blob.slice support as defined in the File API ( http://www.w3.org/TR/FileAPI/). To make it work, we need to get the network embedder layer to add the capability to send the file range. I plan to add the following fields to class FormDataElement: long long m_fileStart; long long m_fileLength; time_t m_fileModificationTime; The individual platform needs to support the followings: 1) Checking if the underlying file has been changed by comparing m_fileModificationTime against the modification time when the file is opened for read. If different, throw an error. This is per the discussion of how we are going to deal with the underlying file change for Blob ( http://lists.w3.org/Archives/Public/public-webapps/2010JanMar/0371.html). 2) Sending the file range denoted by m_fileStart and m_fileLength. In addition, I am going to add ENABLE_BLOB_SLICE flag to control if Blob.slice API should be exposed or not. When a platform implements the necessary support to read the file range, ENABLE_BLOB_SLICE flag can then been turned on. I will make chromium platform and WebKit on mac platform to support the above requirements in order to get Blob.slice work. Please let me know if you have any questions. Thanks, Jian