So far my Firefox canvas demos have only used a small subset of the available canvas commands. To learn about some of the other features I have added the zoom capability to my previous fractal offerings.
View the fractal zoom at your leisure.
The zooming was accomplished by displaying sliced images from an offscreen (hidden by CSS) buffer. This is an extension of the concise description from the Mozilla canvas tutorial. I have also tidied up the previous fractal code somewhat, removing hard-coded constants. It still needs a general reorganisation to remove global variables, but that shall wait for another time.
Because Javascript is not the fastest of languages you may see some delay in the drawing of the fractal. After an extended delay Firefox may pop up a message box asking if you wish to continue. If you say 'yes' then the fractal should get drawn eventually. It is this speed issue that has caused me to draw the fractal in lower than maximal resolution. If you want to zoom in to a high-resolution fractal then have a look at a desktop fractal zoomer such as my old Windows software JM's Mandelbrot Explorer.
Update 11-May-2012: See my WebGL version of the zoomer.