getting a hang of canvas finally, not much here but it does work (I'll post it up live once it's done, for now just screenshots)

Canvas based editor.





Had to use a bit of php trickery and hidden fields to get the save and load working, but they work. Can't really tell from the image but it accepts keyboard input as well, I'm not using static rooms, it can free-scroll, so the arrow keys scroll the level around.

Now I need something better than 3 colored squares for artwork :)