There are several ways to download Youtube video. You can use online tools, software and get the Youtube video file straight away from Internet Explorer temporary internet folder. However, if you want to download multiple videos from YouTube website in one go, you can use the following Firefox add-on.
BYTubeD is a free add-on you can install and use with your Firefox to download Youtube videos in bulk. Perhaps this YouTube video downloader can also download YouTube videos on any page as long as there are linking of YouTube videos on the sites. Just download using the BYTubeD menu item in the Tools menu.
As a result, downloading YouTube videos become handy especially for video with episodes or chapters, you can make it in playlists to play offline in your computer later on.