ASP.NET Core MVC Interview Question #39
What is the difference between server-side and client-side validation?
Controllers, Actions, Model Binding & Action Results Junior Beginner
Quick Interview Answer
Server-side validation executes on the server and must be treated as the authoritative validation layer. Client-side validation runs in the browser and improves usability by displaying errors without a full request when supported.
Detailed Explanation
Server-side validation executes on the server and must be treated as the authoritative validation layer. Client-side validation runs in the browser and improves usability by displaying errors without a full request when supported.
Client-side validation is not a security boundary because a client can disable or bypass JavaScript and submit requests directly. Important rules must always be enforced on the server.
Code Example
<input asp-for="Email" class="form-control" />
<span asp-validation-for="Email" class="text-danger"></span>
@section Scripts {
<partial name="_ValidationScriptsPartial" />
}