===================================================================
--- original.js
+++ change.js
@@ -123,6 +123,10 @@
 	}
 };
 // Handle touch events for jumping
 game.down = function (x, y, obj) {
-	mario.jump();
+	if (mario.isJumping) {
+		mario.isJumping = false;
+	} else {
+		mario.jump();
+	}
 };
\ No newline at end of file