MODX plugin

<?php

function loadAccessibility($token, $config)
{
    $html = "<script>";
    $html .= "(function (w, d, s, l, t, c = {}) {";
    $html .= "w[l] = c;";
    $html .= "w[l].token = t;";
    $html .= "var f = d.getElementsByTagName(s)[0],";
    $html .= "j = d.createElement(s),";
    $html .= "a = new Date().getTime();";
    $html .= "j.async = true;";
    $html .= "j.src = '//wcag.dock.codes/accessibility/' + t + '/start.js?t=' + a;";
    $html .= "f.parentNode.insertBefore(j, f);";
    $html .= "})(window, document, 'script', 'accessibility', '".urlencode($token)."', ".json_encode($config).");";
    $html .= "</script>";
    return $html;
}
$modx->regClientHTMLBlock(loadAccessibility('***', [
    'widget' => true,
    'options' => [
        'contrast' => true,
        'underline' => true,
        /// ...
    ],
    'selectors' => [
        'contrast' => '.wcag-contrast',
        'underline' => '.wcag-underline',
        /// ...
    ],
    /// ...
]));