promise

http://www.ruanyifeng.com/blog/2011/08/a_detailed_explanation_of_jquery_deferred_object.html

http://www.oschina.net/translate/whats-so-great-about-javascript-promises

 http://www.infoq.com/cn/news/2011/09/js-promise

http://www.oschina.net/translate/whats-so-great-about-javascript-promises

http://www.csdn.net/article/2013-08-12/2816527-JavaScript-Promise

 http://www.ruanyifeng.com/blog/2010/04/using_this_keyword_in_javascript.html

http://www.cnblogs.com/iamzhanglei/archive/2013/02/24/2924680.html