GWT boils down to plain web technologies. And no, AFAIKT there is no way to check the size of an uploaded file across web browsers. Most browsers do however have an implicit limitation on the file size, which for majority is about 2 GB.

On 04 Nov 2015, at 10:11, Darran Lofthouse <darran.lofthouse@jboss.com> wrote:

From within GWT is there any option to detect the file size before
uploading?