title: Catching mouse events on html5 canvas when placed in the background
body: <p>I placed the html5 canvas in the background using the following
  style="position:fixed;top:0;left:0;z-index:-1;"</p>
  
  <p>On my window.onload(), I am adding a mouse event listener to the canvas as follows
  canvas.addEventListener('mousemove', onMouseMove, false)
  but unfortunately my canvas is not receiving any mouse events. How do you propagate events down the z-axis? Is it possible to do it without using any external library(if exist)?</p>
  
  <p>I tried searching for it but couldn't found anything relevant so far.</p>