Hi Mmurshedul73 We can't read your mind :-) so we need to ask the following questions to help you: #What version of Firefox are you using? Firefox 37.0.1 for Android? #What version of the Android operating system is on your phone or tablet. Lollipop 4.4? Jellybean 4.1-4.4? Lollipop 5? And what phone or tablet are you using? # Finally please tell us what you did, what happened and what you expected (exact urls of videos that are "invisible". details please!) . Cheers! ...Roland