Robuta

https://dev.to/itihon/using-the-same-validation-logic-on-the-client-and-server-side-with-isomorphic-validation-1eaj
A step by step tutorial of using isomorphic-validation javascript library on the client and server side. Tagged with webdev, javascript, validation, api.
usingvalidationlogicclientserver
https://www.progress.com/documentation/sitefinity-cms/132/extend-custom-designers-with-additional-client-logic-mvc
Extend Sitefinity CMS MVC custom widget designers with additional client logic.
sitefinity cms developmentcustom designersclient logicextendadditional