<iframe src="https://www.linkedin.com/embed/feed/update/urn:li:activity:6346375729873248256" height="400" width="710" frameborder="0" allowfullscreen=""></iframe>
<script>
var i;
var uri = ["6346375729873248256", "6346375729873248256", "6346375729873248256"];
var curi = "";
for (i = 0; i < uri.length; i++) {
  curi = "https://www.linkedin.com/embed/feed/update/urn:li:activity:" + uri[i];
  var iframe = document.createElement('iframe');
  iframe.src = encodeURI(curi);
  iframe.style.width = "710px";
  iframe.style.height = "400px";
  iframe.style.frameborder = "0";
  iframe.style.allowfullscreen = "";
  document.getElementById("linkedin").appendChild(iframe);
  console.log('iframe.contentWindow =', iframe.contentWindow);
}
</script>