*trick to download videos from any sites by an easiest way:
1.first download any download manager.
2.Internet Download Manager is mostly used.
3.then the option "download this video" will be appeared at the upper right side of the video in the case of IDM.

4.Then click on the option "download this video".
5.one box will be appeared,in this box click on "start download" option.
6.your download will start.

ENJOY>