转自https://www.cnblogs.com/koleyang/p/5146623.html
http://dev.dcloud.net.cn/mui/ui/index.html#mask
http://ask.dcloud.net.cn/question/2403
http://ask.dcloud.net.cn/docs/#http://ask.dcloud.net.cn/article/89
原文：https://www.cnblogs.com/smxbo/p/12384676.html