--- title: Theme JS Overview slug: klevu-magento-v4/frontend-theme-js-overview docTags: createdAt: 2024-08-15T09:45:31.556Z --- ## Template JS Documentation Klevu Template JS documentation can be found here [https://docs.klevu.com/template-js](https://docs.klevu.com/template-js). ## Best Practice ### Including Javascript We have added 2 containers to the layout, one in head and one before body end. We recommend adding all Klevu related Javascript to these 2 contains. These 2 contains are named `Klevu_Frontend.head.additional` and `Klevu_Frontend.before.body.end`. This makes it very easy to remove all Klevu scripts from a particular page. We already remove all Klevu Javascript from the checkout page, like so. :::CodeblockTabs module-m2-frontend/view/frontend/layout/checkout\_index\_index.xml ```xml ``` ::: ### Ensure Klevu is ready before accessing it Calling any `klevu` methods before the Klevu JS has loaded will result in errors on the frontend. This may occur if there is a delay in loading the core Klevu library for any reason (e.g code being added being added higher up the page or async being added to the script tag). It is always a good idea to wrap JS containing calls to `klevu` in `window._klvReady.push(function(){})`. This ensures the code wrapped inside `_klvReady` is not fired until `klevu` is available. e.g. ```php renderTag( tagName: 'script', attributes: ['type' => 'text/javascript'], content: $scriptString, textContent: false ) ?> ``` :::hint{type="warning"} Note: `window._klvReady.push` is omitted from the code examples in the rest this documentation for brevity. :::