How do I prevent Chrome going fullscreen while playing youtube videos? I have started observing this ever since I upgraded to Mavericks. Earlier [i.e. on Mountain Lion] if I played any youtube video on fullscreen, only video would be fullscreen, not chrome. 

Now in Mavericks, I am observing that even Chrome app going fullscreen mode. I am not saying it stays fullscreen even after completing the video, but I find it quite annoying. I just want my video to play fullscreen but I don't want my chrome to go to Fullscreen Mode. Anyone else noticed this ? And is it possible to prevent this ?
Chrome takes you into a fullscreen window when you try to play a HTML5 video in fullscreen. On YouTube, if you are using the HTML5 preview/beta instead of the standard Flash (or if you have uninstalled or never installed Flash on your computer), that will continue to happen.

For YouTube at least, make sure Flash is installed and drop out of the HTML5 beta program. This is only a short-term solution, and only applies to video sites that still use Flash.

Try that and see if it work.