> ## Documentation Index > Fetch the complete documentation index at: https://docs.launchmystore.io/llms.txt > Use this file to discover all available pages before exploring further. # App Scripts > Inject JavaScript into every storefront page without theme edits # App Scripts App scripts are JavaScript files your app declares in `app.json` that the storefront loads on every page — no theme edits, no merchant action beyond installing the app. The host inserts a non-blocking loader in `content_for_header` that fetches `/api/apps/extensions` and injects every declared script via `requestIdleCallback`. Use app scripts when your app needs to **run on the storefront** and the effect is delivered entirely by a `