# Zotonic Javascript > Use when creating, refactoring, or reviewing Zotonic JavaScript, template JavaScript tags, wires, actions, Erlang event/2 browser handlers, Cotonic workers/models, MQTT client-server communication, authentication workers, and do_ widgets in Zotonic sites or modules. - Skill: `zotonic/zotonic-javascript` (Agent Skill, multi-file: 2 files) - Install (CLI): `npx skillmds@latest add zotonic/zotonic-javascript` - Raw SKILL.md: https://api.skillmd.com/api/skills/zotonic/zotonic-javascript/raw - Safety review: pending - Works with: Claude Code, Claude.ai, OpenAI Codex - Category: Coding & Dev Tools - Author: zotonic (https://skillmd.com/u/zotonic) - Updated: 2026-09-17 - Page: https://skillmd.com/skills/zotonic/zotonic-javascript --- # Zotonic JavaScript ## First Pass - Inspect nearby templates, JavaScript modules, workers, actions, and Erlang `event/2` handlers before editing; preserve local patterns. - Prefer Zotonic declarative behavior (`{% wire %}`, actions, Cotonic data attributes, workers, and `do_...` widgets) over one-off DOM scripts. - Put reusable JavaScript under the module or site `priv/lib/js` tree and include it with `{% lib %}` from the relevant include template. - Use plain JavaScript and small functional helpers; keep jQuery usage only where existing Zotonic widgets/actions require it. - For source documentation, Erlang actions, scomps, models, and modules should have `-moduledoc`; use those docs as the local source of truth. ## Template JavaScript - Include JavaScript libraries with `{% lib "js/file.js" %}` or multi-file `{% lib %}` blocks. Options include `minify`, `nocache`, `async`, and `defer`; `{% lib ... minify %}` can force minification. - Add module/site JS includes through local include templates such as `_js_include.tpl`, `_admin_js_include.tpl`, `_html_head.tpl`, or `_html_body.tpl` instead of duplicating script tags in pages. - Put page-specific inline JavaScript inside `{% javascript %}...{% endjavascript %}`. It runs after jQuery is initialized; for dynamic content it runs after the DOM update that inserted the template. - Ensure the base template has exactly one `{% script %}`, normally near the end of ``. It emits collected JavaScript from `{% javascript %}`, `{% wire %}`, actions, and related scomps. - Do not put generated JavaScript after `{% script %}` in a page; it will not be included in that page render. - `{% script nostartup %}` omits startup code, and `format="html" | "escapejs" | "js"` controls output format. Use these only when the caller expects a nonstandard script output. - Direct `