Upload to Amazon S3 using HTML5 runtime

Being able to upload files to Amazon S3, especially in HTML5, has been a goal for quite some time and while it was somehow possible in Flash and Silverlight, HTML5 was out of the game. Because Amazon S3 refused to add support for Access-Control-Allow-Origin - that single miraculous header that helps cross-domain AJAX requests to reach the server. Finally, after continuous lament from users, with bleeding shouts like: "Two and a half year later, still no cigar... AWS, Y U MAKIN ME CRY? :'(", Amazon made it happen.

So now it's possible. And here we will tell you how.