Reposition sidebar based on span size

So I am trying to figure out a way to recreate a feature found on popular video sites like YouTube and DailyMotion. The feature is that the depending on the video player’s size the sidebar is either next to, or underneath the video.

I’ll use DailyMotion as my example: http://www.dailymotion.com/video/x1bthva_what-the-tech-ep-201-microsoft-fan-paul-2-11-14_tech

Here’s a video of what I am referring to: http://www.youtube.com/watch?v=ZHyQXmDI-LQ

If you look just below the bottom right, there is an icon to expand the player’s size to use the full width of the layout. As a result, the sidebar moves below the video.

Is there a way to create a layout similar to this? Where I have a video, some content below that, and a sidebar. Then when a button/link is clicked, the div for the video expands to full width of the layout, and the sidebar moves underneath it.