Get Joomla menu custom params (content plugin)
<?php
$app = Factory::getApplication();
$currentMenuItem = $app->getMenu()->getActive();
$customattr = '';
// we want to do something, when we are on pages with itemid 146 or 147
if($currentMenuItem->id == '146' || $currentMenuItem->id == '147') {
// we get data from menu with itemid 167
$dejavnostItemId = $app->getMenu()->getItem(167);
// customattr is field name of parameter, which was set with content plugin
$customattr = $dejavnostItemId->params['customattr'];
}
?>