AJAX version switcher

Rendered documentation provides a version switcher on top of the navigation.

For documentation deployed on docs.typo3.org clicking on the version switcher will perform an AJAX API request that lists all available versions and languages for the current documentation.

For local rendering however, there are two issues that will lead to the version switcher not working properly:

  • Rendered HTML files viewed via the file:/// notation may not execute any JavaScript due to security considerations/configuration of your browser.
  • When viewing HTML files via localhost or a .ddev.site webserver, the AJAX call will fail due to CORS (Cross-Origin Resource Sharing) security restrictions.

Developers of the render-guides project may need to simulate menu rendering though.

For them, navigation can be proxied and simulated.

Making the proxy available

When using the DDEV integration to view the documentation, the DocumentRoot of the DDEV webserver is set to Documentation-GENERATED-temp. This does not contain active PHP files by default.

The file packages/typo3-docs-theme/assets/js/versions-proxy.php in the repository of this project (<https://github.com/TYPO3-Documentation/render-guides>) can act as a simple proxy. You can copy or symlink that file into your Documentation-GENERATED-temp directory, so that it is callable with a URL like:


The PHP proxy passes the URL parameter url on to the actual docs.typo3.org API endpoint, and returns its output locally.

Once the proxy PHP file is in place, the default values of the rendering will take effect already. See Configuring HTML data-attributes on how to fine-tune this.

Details on how the version switcher is implemented

Local rendering is automatically detected via the absence of an environment variable TYPO3AZUREEDGEURIVERSION (see GitHub workflow: deploy-azure-assets).

This allows a Twig function isRenderedForDeployment (defined in packages/typo3-docs-theme/src/Twig/TwigExtension.php of this repository) to conditionally generate output. The Twig template file packages/typo3-docs-theme/resources/template/structure/navigation/navigationHeader.html.twig makes use of that function to define some default HTML data-attributes for out-of-the-box version witcher simulation, once the PHP proxy URL can be called without a 404 error.

The JavaScript is contained in packages/typo3-docs-theme/assets/js/versions.js and contains the code for parsing the JSON response of the API, and sorting the keys appropriately. More details can be found inside the code comments of that file.

When changing this JavaScript, the assets must be rebuilt (ddev npm-build) and documentation must be rendered with the built assets (make docs).

The JavaScript file also contains some logic to set names for known published translations. If a static name is not available, it is resolved to the ISO-code (like "de-de"). The TYPO3 Documentation team can not easily access active server-side code to get an automatic list of languages.

Configuring HTML data-attributes

The following data-attributes on the HTML element <div id="toc-version"> are available:

  • data-override-url-self - This is a full URL starting with https://docs.typo3.org which is used as the simulated page from which the version switching information is retrieved for. For example, https://docs.typo3.org/m/typo3/tutorial-getting-started/12.4/en-us/Concepts/Index.html.
  • data-override-url-proxy - Points to the full URI of the Making the proxy available PHP proxy. This is called due to CORS reasons. The default of this attribute is set to https://render-guides.ddev.site/versions-proxy.php?url=. Unless this file is manually copied to this URL, the proxy will return a 404 failure and inform about the non-working version switcher.

Seeing the simulated output

Once the PHP proxy is in place, open the rendered documentation HTML file in your DDEV/webserver environment (not using a file:/// syntax, because then JavaScript may unavailable), for example


You can then also use the browser's JavaScript console to manipulate the used URLs for rendering, for example:

document.getElementById('toc-version').setAttribute('data-override-url-self', 'https://docs.typo3.org/other/t3docs/render-guides/main/en-us/Developer/InterlinkInventories.html');

This must be performed before actually clicking the version switcher link, because the remote AJAX request is only performed once and then never again without reloading the page.