Can’t play video on full screen on coovachilli popup page

I am using openwrt+coovachilli in my router, and videos are stored into usb. Everything is working perfect in browser. I can play, stop, download and full screen videos but in popup I only do play and pause.
I used video tag to play videos and nginx server. Below is my code to play video:-

There is full screen button on popup page but when I click on it nothing happens. I want to play it in full screen in popup page as well. Thanks in advance.