Joint = null;
               }
            }
         
            world.Step(1 / 60, 10, 10);
            world.DrawDebugData();
            world.ClearForces();
         };
         
         //helpers
         
         //http://js-tut.aardon.de/js-tut/tutorial/position.html
         function getElementPosition(element) {
            var elem=element, tagname="", x=0, y=0;
           
            while((typeof(elem) == "object") && (typeof(elem.tagName) != "undefined")) {
               y += elem.offsetT