Defines the name of the file uploading event. Fired every time when fileuploader get status for the upload. Return false in order to cancel uploading file. Function takes arguments evt and ui. Use ui.fileId to get unique identifier of the file. Use ui.filePath to get the name of the uploaded file. Use ui.totalSize to get the file size of the uploaded file. Use ui.uploadedBytes to get uploaded bytes. Use ui.fileStatus to get current file status. Use ui.owner in order to access the igUpload widget object.
Target Platforms: Windows 8.1, Windows 8.1, Windows 8, Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2
