JavaScript event for canvas resize

Question

It appears that altering the dimensions of a canvas clears any drawing already done on that canvas.

Is there an event that fires on canvas resize, so I can hook it a

Answer 1

save the canvas state as imageData and then redraw it after resizing

var imgDat=ctx.getImageData(0,0,ctx.canvas.width,ctx.canvas.height)

after resize

ctx.putImageData(imgDat,0,0)