这一章介绍一个游戏：Engineer。这里将会你讲解<canvas>标签以及怎样使用它来给应用程序加速。这一章你会学到“事件”这个概念以及一些widget的精华。-This chapter describes a game: Engineer. Here will you explain <canvas> Labels and how to use it to accelerate to the application. In this chapter you will