Hosting
What is the aspnet_client Folder?
This folder is automatically created when you enable the ASP.net extension on your site and it is is related to ASP.net runtime validation.
This folder contains the client-side code used by some of the ASP.NET Web Form controls (namely validation, SmartNavigation). If your aspnet_client directory is missing, you may encounter errors with your application such as “Unable to find script library To resolve this, you can manually copy the folder to the root directory of your domain name.