Video and audio: playing media in the browser - HTML5 in Action - page 361

To give users the ability to turn the frame on and off, you'll need a button in the menu from
listing 8.11 :
<button>Framed</button>
Because it's on the menu, you can take advantage of the existing click-handling code
for that—the additional cases for the switch statement are shown in the following list-
ing—and add them to the handler from listing 8.11 .
Listing 8.13. index.html—Handler for the Frame button
With this next listing, you need to adjust the draw() function to draw the frame.
Listing 8.14. index.html—Adjust the draw() function to show the frame
And that's it! You should now be able to get a frame to appear over the video playback at
the click of a button. In the next step you'll learn how to adjust how the two images, the
frame and video, are composed (combined) together on the Canvas.