TiddlyWiki executes any ActionWidgets found in tiddlers with the following system tags during startup:

• Executed during initial startup:
  • $:/tags/StartupAction (executed on all platforms)
  • $:/tags/StartupAction/Browser (only executed when running in the browser)
  • $:/tags/StartupAction/Node (only executed when running under Node.js)
• Executed after startup rendering:
  • Introduced in v5.1.23 $:/tags/StartupAction/PostRender (only executed when running in the browser)

Initial Startup Actions

The initial startup actions are useful for customising TiddlyWiki according to environmental factors such as the screen size. For example, the following action widgets when placed in a tiddler tagged $:/tags/StartupAction/Browser will cause the sidebar to be hidden by default when the screen width is less than 1000 pixels:

<$reveal type="lt" state="$:/info/browser/screen/width" text="3000">
<$action-setfield $tiddler="$:/state/sidebar" $value="no"/>
</$reveal>

<$reveal type="gteq" state="$:/info/browser/screen/width" text="3000">
<$action-setfield $tiddler="$:/state/sidebar" $value="yes"/>
</$reveal>

Introduced in v5.1.20 This example switches to the language plugin matching the language reported by the browser:

<$action-setfield $tiddler="$:/language" text={{{ [[$:/languages/en-GB]] [plugin-type[language]sort[description]removeprefix[$:/languages/]] +[prefix{$:/info/browser/language}] ~[[en-GB]] +[addprefix[$:/languages/]] }}}/>

Note that global macros are not available within initial startup action tiddlers by default. If you need to access them then you'll need to explicitly include them with an Pragma: \import at the top of the tiddler:

\import [subfilter{$:/core/config/GlobalImportFilter}]

Post-Render Startup Actions

Introduced in v5.1.23 Post-render startup actions occur after the TiddlyWiki user interface has been rendered. This makes it possible to perform actions that depend on the rendered display (such as displaying modals).