 <p>The <a href="http://en.wikipedia.org/wiki/Canvas_element" rel="nofollow noreferrer">Canvas element</a> is essentially a drawing canvas that can be painted on programmatically; a sort of scriptable bitmap drawing tool for the web.</p> <p>I suppose the "amazing" thing about it, apart from the fact that we can now all create web-based MS Paint clones with ease, is that you have a much richer, completely free-form area for creating complex graphics client-side and on-the-fly. You can draw pretty graphs, or do things with photos. Allegedly, you can also do animation!</p> <p><a href="https://developer.mozilla.org/en/Canvas_tutorial" rel="nofollow noreferrer">Mozilla's Developer Center has a reasonable tutorial</a> if you want to try it out.</p>