https://developer.mozilla.org/en-US/docs/Web/API/Window/sessionStorage
http://www.cnblogs.com/yuzhongwusan/archive/2011/12/19/2293347.html
https://developer.mozilla.org/en-US/docs/Web/API/Window/sessionStorage
http://www.cnblogs.com/yuzhongwusan/archive/2011/12/19/2293347.html