function MyInlineJavaScript($action)
{
    $action->inlineScript('alert("Here is an alert!")');
    return true;
}
 
function MyJavaScriptFile($action)
{
    $action->script('/path/to/myscript.js');
    return true;
}   
     
Event::addHandler('EndShowScripts', 'MyInlineJavaScript');
Event::addHandler('EndShowScripts', 'MyJavaScriptFile');