A string that contains the virtual path where resources(scripts, icons) are located.
You have to set this property to the path of the client java script files since it is required to render the control on the page correctly. If the resources are not in the specified directory, they will not show up and you will receive a client java script error.
This property can be set in the application's Web.config file. Use this syntax in the "appSettings" section of the config file:
Refer to ImageUrl