http://qydev.weixin.qq.com/wiki/index.php?title=%E5%BE%AE%E4%BF%A1JS-SDK%E6%8E%A5%E5%8F%A3#.E6.AD.A5.E9.AA.A4.E4.B8.80.EF.BC.9A.E5.BC.95.E5.85.A5JS.E6.96.87.E4.BB.B6
