JavaScript has become the most popular programming language in the world. It has attained that position by being easy to use and powerful in its capabilities. It wasn't always that way but today it can be used to build virtually any application you desire. With the addition of HTML5 and CSS3, it allows for wonderfully animated and powerful web sites and applications without having to use other technologies such as Adobe Flash. JavaScript has also become much more standardized across the multiple browsers in use today. With the recent proliferation of libraries and frameworks that many developers use, the focus has shifted towards these new tools, but they still rely on native JavaScript. And these libraries and frameworks can greatly increase the size of your code as well as slowing down performance. This book covers best practices for coding in straight JavaScript as well as pointing out many areas for optimization. The goal is to help programmers produce smaller and faster JavaScript applications. Even programmers using frameworks and libraries can benefit from understanding the performance trade-offs they make when using those tools.