Help creating a Conditional tag (Output Modifier)

Make a stab at it, and we'll be here to help if you get stuck. Even now, it usually takes me two or three tries to get even the simplest snippet to work right. When a snippet works right the first time, it's cause for celebration

Something like this should do the trick:

$parent = $modx->resource->get('parent');
switch ($parent) {
    case 4:
        return '[[$this-chunk]]';
        break;
    case 8:
        return "[[$that-chunk]]";
        break;
    default:
        return;
        break;
}
return;

While you cannot use a chunk directly in PHP code, you can return a set of chunk tags. MODx will process the chunk tag as usual on the next pass through the parser. While you could use the API chunk parsing functions, it's easier to let MODx do the heavy lifting

$modx->regClientCSS('assets/css/style.css');

As far as using the $modx->regClient...() API functions, they're pretty easy to use. Just define the CSS, HTML, or JS block you want inserted, or a path to a file, and MODx takes care of rest of it.

$css = '<style>
.blue {color:blue;}
.red {color:red;}
</style>';
$modx->regClientCSS($css);
$js = 'assets/js/myjsfile.js';
$modx->regClientStartupScript($js);

So how does the connection between the snippet and chunk work. In other words when this chunk is selected on the TV how does Modx know to use the css & JS that we registered in the snippets.