gooey

As you probably know, window_set_fullscreen() does not work on HTML5. So after searching online, I basically copy/pasted a small Javascript code for a GMS1 extension found in this forum post (full credit to the original author), in order to create a button that is added on top of the game canvas (I chose the bottom right corner but you can change that on the provided script), that lets you toggle full screen on or off. Check out the demo "game" above.