Sep 12, 2005, 01:48am EDT
To draw, hold down the ALT key then click and drag on any web page. The results get saved locally in a user preference so they’ll still be there when you return to the page. You can press CTRL+SHIFT+K to erase all the lines.
The script isn’t really usable; it’s pretty slow and there’s this annoying bug where you can’t click through a transparent canvas unless the layer under it is using absolute positioning. I provided a hotkey (CTRL+SHIFT+T) to toggle the canvas on and off so you can still get to content, but it makes it painful to use the script. It’s more of a demo of the possibilites of canvas in Firefox.
Update: Greasemonkey 0.6.2 is compatible with Firefox 1.5b1.