function drawABTest(ratio) {
  const random = Math.floor(Math.random() * 100);
  return random < ratio;
}

(function () {
  const queryString = window.location.search;
  const urlParams = new URLSearchParams(queryString);
  const opti_param_value = urlParams.get("ab_opti_pbstck");
  const ab_test = drawABTest(50);
  if (ab_test || opti_param_value === "opti") {
    // Opti Digital
    const pubid = "46980923";
    const script = document.createElement("script");
    script.type = "text/javascript";
    script.async = true;
    script.src = `https://optiyield.opti-digital.com/pfc/?pubid=${pubid}`;

    const meta = document.createElement("meta");
    meta.name = "ad:ab_opti_pbstck";
    meta.content = "opti";
    document.head.appendChild(script);
    document.head.appendChild(meta);
  } else if ( !ab_test || opti_param_value === "pbstck"){
    // Pubstack
    const meta = document.createElement("meta");
    meta.name = "ad:ab_opti_pbstck";
    meta.content = "pbstck";
    document.head.appendChild(meta);
  }
})();