参考：
http://ued.taobao.com/blog/2012/06/debug-with-chrome-dev-tool/
http://guoshuang.com/frontend/chrome-console-command/
http://www.cnblogs.com/wukenaihe/archive/2013/01/27/javascript%E8%B0%83%E8%AF%95.html
http://han.guokai.blog.163.com/blog/static/136718271201321402514114/