numeration

2-ui/3-event-details/4-mouse-drag-and-drop/article.md

@@ -156,10 +156,10 @@ ball.onmousedown = function(event) {
     moveAt(event.pageX, event.pageY);
   }
 
-  // (3) move the ball on mousemove
+  // move the ball on mousemove
   document.addEventListener('mousemove', onMouseMove);
 
-  // (4) drop the ball, remove unneeded handlers
+  // drop the ball, remove unneeded handlers
   ball.onmouseup = function() {
     document.removeEventListener('mousemove', onMouseMove);
     ball.onmouseup = null;