Run games/demos built directly in the url
Example: https://g01f.eu?w=573&h=400#u=v=2;x=y=300;setInterval('c.fillRect(x,y,3,3);x+=u=x%3C0||x>w-3?-u:u;y+=v=y%3C0||y>h-3?-v:v',10)
See github.com/jmdejong/g01f for instructions and documentation and more examples