http://www.cnblogs.com/crazyacking/p/5456347.html#_label00这个最容易看懂
http://www.cnblogs.com/ITtangtang/p/3926665.html
http://blog.csdn.net/meng2602956882/article/details/16951643
http://www.cnblogs.com/Scott007/p/3269018.html#undefined
http://www.cnblogs.com/suman/archive/2010/10/23/1858864.html
追加文件的三种方式
http://blog.csdn.net/malik76/article/details/6408726/