JavaScript call()的解释
http://www.cnblogs.com/guopei/archive/2011/04/17/2019045.html
http://www.cnblogs.com/PrimerDotNet/archive/2011/04/14/2015548.html
http://rt0d.iteye.com/blog/1003613
http://www.cnblogs.com/PrimerDotNet/archive/2011/04/14/2015548.html
http://rt0d.iteye.com/blog/1003613