Halmond's Laboratory: http://www.byronknoll.com/dungeon.html
Navigate using arrow keys, mouse drag, or touch. Zoom in/out using your browser's zoom tool. This map is used with the author's permission.
Creating a map involves manually tracing the coordinates of walls and obstacles. The coordinates match the pixel positions of the background image (with the origin in the top-left). One way to find the coordinates is to load an image using this library (without any walls), navigate to a place you want to record, and press 'space'. This will log the coordinates at the crosshair into your browser's developer console. You can press '/' to adjust the movement speed to help fine-tune coordinates.
Contact me at firstname.lastname@example.org if you have any questions or feature requests.