前端实现在线预览pdf、word、xls、ppt等文件

https://blog.csdn.net/Aria_Miazzy/article/details/100069259?utm_medium=distribute.pc_relevant_bbs_down.none-task-blog-baidujs-1.nonecase&depth_1-utm_source=distribute.pc_relevant_bbs_down.none-task-blog-baidujs-1.nonecase