PHP example for Accessing the Joomla Framework via an AJAX Call

gistfile1.txt

if (empty($_POST["catid"])){
    $return["error"] = true;
    $return["msg"] = "Unidentified category ID.";
} else {
    $return["error"] = false;
    $db->setQuery('SELECT title FROM #__categories WHERE id='.$_POST["catid"]); 
    $category = $db->loadRow();
    if (is_array($category)){
        if ($category[0] == "Portfolio"){
            $category[0] = "Project Study";
        }
        $return["msg"] = $category[0];
    }
}
echo json_encode($return);