Download Youtube videos in ".mp4" format

Below is the code to download a video from the you tube,copy-paste this code into the address bar when your desired video starts buffering.

copy this script into address bar:

javascript:if(document.location.href.match(/http:\/\/[a-zA-Z\.]*youtube\.com\/watch/)){document.location.href='http://www.youtube.com/get_video?fmt='+(isHDAvailable?'22':'18')+'&video_id='+swfArgs['video_id']+'&t='+swfArgs['t']}