# Progressive enhancement > How Apogee decides when a component needs JavaScript, and the mechanical no-js / js system that keeps the fallback real. URL: https://apogee.avaui.dev/docs/progressive-enhancement Last updated: 2026-10-15 How Apogee decides when a component needs JavaScript, and the mechanical no-js / js system that keeps the fallback real. Last updated October 15, 2026 Apogee ships **zero JavaScript by default**. No UI-framework runtime rides along with a component — everything is vanilla HTML, CSS, and (only where earned) a small scoped ` ``` The second line turns on pressed feedback on iPhone and iPad: Safari skips `:active` unless the page listens for touches. Components show that state through the `press` utility in the tokens file. Two Tailwind variants key off that class: `no-js:` and `js:`. The rule that follows from them: - A component’s **default, no-variant state is the working, JS-off fallback** — it has to be usable on its own. - Any **JS-only affordance** — a control that does nothing without the script — is gated with `no-js:hidden`, so it disappears when JS is off instead of sitting there as a dead button. Tag’s remove button is the real example: ```astro ``` - A component that swaps to an **enhanced presentation** once its script runs adds a readiness class to its own root (`is-ready`), so nothing flashes and the default CSS state keeps holding as the fallback until then. No JS-off page should ever show a broken or dead control — worst case, an affordance is simply absent and the underlying content still works (Carousel without JS is a plain scroll list; Tabs without JS shows every panel stacked). ## Finding what ships JS The docs sidebar marks every component whose registry entry sets `usesJs: true` with a **JS** badge — that’s your signal a component includes a script island, and its doc page opens with a `` explaining what the script does and what the no-JS fallback looks like. ## Reduced motion Every animation — CSS or JS-driven — respects `prefers-reduced-motion`. Not optional, checked on every animated component. ## Not now - No `client:*` hydration directives or framework islands (React/Vue) — an Apogee script is a plain `