How To Download Facebook Videos
This trick only works on Facebook.com and will not work in the app, so you will need to go to the Facebook browser first. Then find the video you want to download, select Share> Copy link.
URL box on Facebook video
A small box will appear with the URL of the video. Copy the link and paste it into a new tab or address bar in the window. Then change the www address to mbasic. When you're done, tap Enter on your keyboard. This changes the address to the main address of the mobile interface that allows you to download the video. If you did it right, the screen will look strange as if you are trying to look at the Facebook application in your browser.
Open the video in a new tab
Then right-click on the video and select Open link in a new tab from the menu. The new tab will not contain any Facebook attachments, such as comments or a Like button, on the video. This will only be a video.
Save a Facebook video to your computer
From there, right-click on the video and select Save Video As Menu from the menu. Then save it to your computer just like you would any other video or photo. Once the video is stored on your computer, you can open it for playback in your standard video player.