Apparently, the following does the job:
var myAds = document.getElementById("myAds");
var frag, elem;
frag = document.createDocumentFragment();
elem = document.createElement('ins');
frag.appendChild(elem);
elem.className += "adsbygoogle";
elem.setAttribute("style", "display:inline-block;width:160px;height:600px");
elem.setAttribute("data-ad-client", "ca-pub-1234567890");
elem.setAttribute("data-ad-slot", "0987654321");
myAds.appendChild(frag);