====== F.Y.I. ======
http://www.ruanyifeng.com/blog/2009/08/learning_javascript_closures.html


  * 闭包的工作原理： http://www.frontopen.com/1702.html
  * Javascript内存分配：  http://www.cnblogs.com/kycool/archive/2011/11/30/2268653.html
  * 栈内存or堆内存： http://www.tuicool.com/articles/m2queq
  * 闭包： http://www.cnblogs.com/TomXu/archive/2012/01/31/2330252.html