htmx

Server-rendered UI fragments can be updated by adding hx-* attributes to HTML elements and returning HTML fragments from server endpoints. This enables hypermedia-driven interactions for fine-grained partial updates without writing client-side JavaScript.

Form validation in a hypermedia-driven web application is handled by submitting forms via htmx requests and returning robust validation responses as HTML fragments. This allows the server to render inline validation errors directly into the existing page.

Out-of-band updates work for modals and inline editing in traditional web apps by returning multiple HTML fragments from a single server request. This allows targeted updates to page panels and modal surfaces simultaneously alongside the primary content swap.

Htmx requires CSRF protections and safe headers for partial requests to secure fragment endpoints. The server must satisfy requirements for returning HTML fragments by validating stable targets and ensuring request headers are properly sanitized.

You should not use a server-driven UI approach when an application requires highly complex, state-heavy client-side interactions that go beyond simple fragment updates, infinite scrolling, or in-page panels. Heavy state management is better suited for full frontend frameworks.

Infinite scrolling is implemented using partial renders and fragment endpoints by appending HTML fragments to a target list as the user scrolls. The server returns the next set of rendered items to update the UI surface dynamically.