上传文件，file-input插件
https://www.cnblogs.com/cyc-ghost/p/12841625.html
https://blog.csdn.net/zzq900503/article/details/73499514
例子
https://plugins.krajee.com/file-input/demo
https://plugins.krajee.com/file-advanced-usage-demo
https://plugins.krajee.com/file-krajee-explorer-demo#krajee-explorer-2
https://plugins.krajee.com/file-preview-management-demo#preview-pdf
文档
https://plugins.krajee.com/file-input
https://plugins.krajee.com/file-input/plugin-options
https://plugins.krajee.com/file-input/plugin-events
https://plugins.krajee.com/file-input/plugin-methods
确认是否删除，jquery confirm插件
https://plugins.krajee.com/file-plugin-methods-demo#delete-validation-1
jquery confirm 插件帮助文档
https://craftpip.github.io/jquery-confirm/
https://www.jquery-confirm.cn/
https://www.jq22.com/demo/jqueryConfirm20160413/