How do you download multiple files from youtube using firefox add on download helper?
If you mouse-select a portion of a web page containing any number of links to youtube video pages and right click, the context menu shows an entry labeled ‘Download video(s) from selected link(s)’. Click on it. All the videos are queued for download. By default, downloads are performed one by one to protect your bandwidth. From the add-on preferences, you can choose ‘Normal’ mode rather than default ‘One by one’. All downloads will start at the same time (but this might not be a good idea). Alternative: enable the ‘History’ feature of DownloadHelper. Start watching the videos you want on YouTube, then open the history dialog. Select the videos you need (hold CTRL to select multiple), then choose ‘Download’ button.