运行出错

[xxingjjing]

1. 再微信开发工具中调试出错：
   Cannot set property 'pixelRatio' of undefined;at SelectorQuery callback function
   TypeError: Cannot set property 'pixelRatio' of undefined
2. 改为真机调试仍然出错：
   [publib]:147 eval script evaluate_id #12 failed TypeError: Cannot set property 'ontouchstart' of undefined