# Client-Side Validation

Browsers check HTML attributes such as required on their own; ASP.NET Core's validation scripts check your model's data annotations in the browser, from the data-val attributes the tag helpers write.

![Cheat sheet: Client-Side Validation](https://fsdtrainingmedia.blob.core.windows.net/public/images/2026/11/dc1d6146fe2e4b86ae746a683695b398.webp)

- Category: ASP.NET Core
- Level: Apprentice
- Tags: aspnet-core, Client-Side Validation, Constraint validation, html, required
- Updated: November 3, 2026

Source: https://www.ask-codey.com/cheat-sheets/model-binding-and-validation-client-side-validation-cheat-sheet