window.addEventListener('load', function() {
  var canvas = document.getElementById("drawSurface"),
  context = canvas.getContext("2d");
  if (window.navigator.pointerEnabled) {
    canvas.addEventListener("pointermove", paint, false);
	if(window.navigator.maxTouchPoints>1)
		document.querySelector("#support").innerText = "Your hardware supports multi-touch!";
  } 
  else {
	//Provide fallback for user agents that do not support Pointer Events
    canvas.addEventListener("mousemove", paint, false);
  }
  function paint(event) {
	if(event.buttons>0)
		context.fillRect(event.clientX, event.clientY, 5, 5);
  }
});