Client-side scripts can also be used to perform validation of data entered into forms, either using JavaScript or some new features of HTML5. It is possible to generate a query client-side but it ...

a MaxLength property that allows the developer using the annotation to specify the maximum number of characters allowed: The first step is to create a JavaScript function that registers a validation ...

no client-side validation happens. Other forums suggest copying the aspnet_client folder to the project root, but, on my machine, C Inetpub\wwwroot\aspnet_client\system_web\4_0_30319 is empty.