t.getElementById("wslm_status").textContent = " websocket connection CLOSED ";
		}
	} catch(exception) {
		alert('<p>Error' + exception);  
	}

	var canvas = document.createElement('canvas');
	canvas.height = 300;
	canvas.width = 480;
	ctx = canvas.getContext("2d");

	document.getElementById('wslm_drawing').appendChild(canvas);

	canvas.addEventListener('mousemove', ev_mousemove, false);
	canvas.addEventListener('mousedown', ev_mousedown, false);
	canvas.addEventListener('mouseup', ev_mouseup, false);

	off