With HTML5 and the discontinuity of Flash Player in most modern web browsers, Gmail stopt using a Flash player movie (.swf) as the default uploader of files as attachment when composing emails.
Do someone know the approximate date that transition or discontinuity took place? Also, I know that they used a proprietary swf which came from a small company.
I am pretty sure because by the date they started using Flash (2011 I believe), I was developing a file manager via web (like Dropbox or Google Drive), and my boss wanted an uploader capable of selecting multiple files at a time and including a progress bar. I searched for Java solutions but he didn't want Java, so I discovered this paid swf solution, and we purchased it.
Curiously enough, a month later, I saw that Gmail had incorporated the capability, and when looking for the .swf file I discovered that it was exactly the same solution I was using, I was very surprised that the guys at Google did not develop their own solution (it frankly was a very easy code, though we purchased it because it took more time to develop from scratch). Does someone remember the name of that small company or the name of the swf "plugin"?
Well, HTML5 is perfectly capable of achieving this with ajax and by now Flash is definitely not recommended.
Take a look at this amazing plugin. Everything you need. I personally use it with PHP on the back end.
FileUploader - Scroll to the bottom of the page for examples
Screenshot Example